Since Requests v2.3.0, Requests has been vulnerable to potentially leaking Proxy-Authorization headers to destination servers, specifically during redirects to an HTTPS origin. This is a product of how rebuild_proxies is used to recompute and reattach the Proxy-Authorization header to requests when redirected. Note this behavior has only been observed to affect proxied requests when credentials are supplied in the URL user information component (e.g. https://username:password@proxy:8080).
Current vulnerable behavior(s):
HTTP → HTTPS: leak
HTTPS → HTTP: no leak
HTTPS → HTTPS: leak
HTTP → HTTP: no leak
For HTTP connections sent through the proxy, the proxy will identify the header in the request itself and remove it prior to forwarding to the destination server. However when sent over HTTPS, the Proxy-Authorization header must be sent in the CONNECT request as the proxy has no visibility into further tunneled requests. This results in Requests forwarding the header to the destination server unintentionally, allowing a malicious actor to potentially exfiltrate those credentials.
The reason this currently works for HTTPS connections in Requests is the Proxy-Authorization header is also handled by urllib3 with our usage of the ProxyManager in adapters.py with proxy_manager_for. This will compute the required proxy headers in proxy_headers and pass them to the Proxy Manager, avoiding attaching them directly to the Request object. This will be our preferred option going forward for default usage.
Patches
Starting in Requests v2.31.0, Requests will no longer attach this header to redirects with an HTTPS destination. This should have no negative impacts on the default behavior of the library as the proxy credentials are already properly being handled by urllib3's ProxyManager.
For users with custom adapters, this may be potentially breaking if you were already working around this behavior. The previous functionality of rebuild_proxies doesn't make sense in any case, so we would encourage any users impacted to migrate any handling of Proxy-Authorization directly into their custom adapter.
Workarounds
For users who are not able to update Requests immediately, there is one potential workaround.
You may disable redirects by setting allow_redirects to False on all calls through Requests top-level APIs. Note that if you're currently relying on redirect behaviors, you will need to capture the 3xx response codes and ensure a new request is made to the redirect destination.
import requests
r = requests.get('http://github.com/', allow_redirects=False)
Credits
This vulnerability was discovered and disclosed by the following individuals.
Dennis Brinkrolf, Haxolot (https://haxolot.com/)
Tobias Funke, (tobiasfunke93@gmail.com)
When making requests through a Requests Session, if the first request is made with verify=False to disable cert verification, all subsequent requests to the same origin will continue to ignore cert verification regardless of changes to the value of verify. This behavior will continue for the lifecycle of the connection in the connection pool.
Remediation
Any of these options can be used to remediate the current issue, we highly recommend upgrading as the preferred mitigation.
Upgrade to requests>=2.32.0.
For requests<2.32.0, avoid setting verify=False for the first request to a host while using a Requests Session.
For requests<2.32.0, call close() on Session objects to clear existing connections if verify=False is used.
psf/requests (requests)
### [`v2.32.2`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2322-2024-05-21)
[Compare Source](https://togithub.com/psf/requests/compare/v2.32.1...v2.32.2)
**Deprecations**
- To provide a more stable migration for custom HTTPAdapters impacted
by the CVE changes in 2.32.0, we've renamed `_get_connection` to
a new public API, `get_connection_with_tls_context`. Existing custom
HTTPAdapters will need to migrate their code to use this new API.
`get_connection` is considered deprecated in all versions of Requests>=2.32.0.
A minimal (2-line) example has been provided in the linked PR to ease
migration, but we strongly urge users to evaluate if their custom adapter
is subject to the same issue described in CVE-2024-35195. ([#6710](https://togithub.com/psf/requests/issues/6710))
### [`v2.32.1`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2321-2024-05-20)
[Compare Source](https://togithub.com/psf/requests/compare/v2.32.0...v2.32.1)
**Bugfixes**
- Add missing test certs to the sdist distributed on PyPI.
### [`v2.32.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2320-2024-05-20)
[Compare Source](https://togithub.com/psf/requests/compare/v2.31.0...v2.32.0)
**Security**
- Fixed an issue where setting `verify=False` on the first request from a
Session will cause subsequent requests to the *same origin* to also ignore
cert verification, regardless of the value of `verify`.
(https://github.com/psf/requests/security/advisories/GHSA-9wx4-h78v-vm56)
**Improvements**
- `verify=True` now reuses a global SSLContext which should improve
request time variance between first and subsequent requests. It should
also minimize certificate load time on Windows systems when using a Python
version built with OpenSSL 3.x. ([#6667](https://togithub.com/psf/requests/issues/6667))
- Requests now supports optional use of character detection
(`chardet` or `charset_normalizer`) when repackaged or vendored.
This enables `pip` and other projects to minimize their vendoring
surface area. The `Response.text()` and `apparent_encoding` APIs
will default to `utf-8` if neither library is present. ([#6702](https://togithub.com/psf/requests/issues/6702))
**Bugfixes**
- Fixed bug in length detection where emoji length was incorrectly
calculated in the request content-length. ([#6589](https://togithub.com/psf/requests/issues/6589))
- Fixed deserialization bug in JSONDecodeError. ([#6629](https://togithub.com/psf/requests/issues/6629))
- Fixed bug where an extra leading `/` (path separator) could lead
urllib3 to unnecessarily reparse the request URI. ([#6644](https://togithub.com/psf/requests/issues/6644))
**Deprecations**
- Requests has officially added support for CPython 3.12 ([#6503](https://togithub.com/psf/requests/issues/6503))
- Requests has officially added support for PyPy 3.9 and 3.10 ([#6641](https://togithub.com/psf/requests/issues/6641))
- Requests has officially dropped support for CPython 3.7 ([#6642](https://togithub.com/psf/requests/issues/6642))
- Requests has officially dropped support for PyPy 3.7 and 3.8 ([#6641](https://togithub.com/psf/requests/issues/6641))
**Documentation**
- Various typo fixes and doc improvements.
**Packaging**
- Requests has started adopting some modern packaging practices.
The source files for the projects (formerly `requests`) is now located
in `src/requests` in the Requests sdist. ([#6506](https://togithub.com/psf/requests/issues/6506))
- Starting in Requests 2.33.0, Requests will migrate to a PEP 517 build system
using `hatchling`. This should not impact the average user, but extremely old
versions of packaging utilities may have issues with the new packaging format.
### [`v2.31.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2310-2023-05-22)
[Compare Source](https://togithub.com/psf/requests/compare/v2.30.0...v2.31.0)
**Security**
- Versions of Requests between v2.3.0 and v2.30.0 are vulnerable to potential
forwarding of `Proxy-Authorization` headers to destination servers when
following HTTPS redirects.
When proxies are defined with user info (`https://user:pass@proxy:8080`), Requests
will construct a `Proxy-Authorization` header that is attached to the request to
authenticate with the proxy.
In cases where Requests receives a redirect response, it previously reattached
the `Proxy-Authorization` header incorrectly, resulting in the value being
sent through the tunneled connection to the destination server. Users who rely on
defining their proxy credentials in the URL are *strongly* encouraged to upgrade
to Requests 2.31.0+ to prevent unintentional leakage and rotate their proxy
credentials once the change has been fully deployed.
Users who do not use a proxy or do not supply their proxy credentials through
the user information portion of their proxy URL are not subject to this
vulnerability.
Full details can be read in our [Github Security Advisory](https://togithub.com/psf/requests/security/advisories/GHSA-j8r2-6x86-q33q)
and [CVE-2023-32681](https://nvd.nist.gov/vuln/detail/CVE-2023-32681).
### [`v2.30.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2300-2023-05-03)
[Compare Source](https://togithub.com/psf/requests/compare/v2.29.0...v2.30.0)
**Dependencies**
- ⚠️ Added support for urllib3 2.0. ⚠️
This may contain minor breaking changes so we advise careful testing and
reviewing https://urllib3.readthedocs.io/en/latest/v2-migration-guide.html
prior to upgrading.
Users who wish to stay on urllib3 1.x can pin to `urllib3<2`.
### [`v2.29.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2290-2023-04-26)
[Compare Source](https://togithub.com/psf/requests/compare/v2.28.2...v2.29.0)
**Improvements**
- Requests now defers chunked requests to the urllib3 implementation to improve
standardization. ([#6226](https://togithub.com/psf/requests/issues/6226))
- Requests relaxes header component requirements to support bytes/str subclasses. ([#6356](https://togithub.com/psf/requests/issues/6356))
### [`v2.28.2`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2282-2023-01-12)
[Compare Source](https://togithub.com/psf/requests/compare/v2.28.1...v2.28.2)
**Dependencies**
- Requests now supports charset_normalizer 3.x. ([#6261](https://togithub.com/psf/requests/issues/6261))
**Bugfixes**
- Updated MissingSchema exception to suggest https scheme rather than http. ([#6188](https://togithub.com/psf/requests/issues/6188))
### [`v2.28.1`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2281-2022-06-29)
[Compare Source](https://togithub.com/psf/requests/compare/v2.28.0...v2.28.1)
**Improvements**
- Speed optimization in `iter_content` with transition to `yield from`. ([#6170](https://togithub.com/psf/requests/issues/6170))
**Dependencies**
- Added support for chardet 5.0.0 ([#6179](https://togithub.com/psf/requests/issues/6179))
- Added support for charset-normalizer 2.1.0 ([#6169](https://togithub.com/psf/requests/issues/6169))
Configuration
📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).
🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.
♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.
🔕 Ignore: Close this PR and you won't be reminded about this update again.
[ ] If you want to rebase/retry this PR, check this box
This PR contains the following updates:
>=2.28, <2.31->>=2.32.2, <2.33GitHub Vulnerability Alerts
CVE-2023-32681
Impact
Since Requests v2.3.0, Requests has been vulnerable to potentially leaking
Proxy-Authorizationheaders to destination servers, specifically during redirects to an HTTPS origin. This is a product of howrebuild_proxiesis used to recompute and reattach theProxy-Authorizationheader to requests when redirected. Note this behavior has only been observed to affect proxied requests when credentials are supplied in the URL user information component (e.g.https://username:password@proxy:8080).Current vulnerable behavior(s):
For HTTP connections sent through the proxy, the proxy will identify the header in the request itself and remove it prior to forwarding to the destination server. However when sent over HTTPS, the
Proxy-Authorizationheader must be sent in the CONNECT request as the proxy has no visibility into further tunneled requests. This results in Requests forwarding the header to the destination server unintentionally, allowing a malicious actor to potentially exfiltrate those credentials.The reason this currently works for HTTPS connections in Requests is the
Proxy-Authorizationheader is also handled by urllib3 with our usage of the ProxyManager in adapters.py withproxy_manager_for. This will compute the required proxy headers inproxy_headersand pass them to the Proxy Manager, avoiding attaching them directly to the Request object. This will be our preferred option going forward for default usage.Patches
Starting in Requests v2.31.0, Requests will no longer attach this header to redirects with an HTTPS destination. This should have no negative impacts on the default behavior of the library as the proxy credentials are already properly being handled by urllib3's ProxyManager.
For users with custom adapters, this may be potentially breaking if you were already working around this behavior. The previous functionality of
rebuild_proxiesdoesn't make sense in any case, so we would encourage any users impacted to migrate any handling of Proxy-Authorization directly into their custom adapter.Workarounds
For users who are not able to update Requests immediately, there is one potential workaround.
You may disable redirects by setting
allow_redirectstoFalseon all calls through Requests top-level APIs. Note that if you're currently relying on redirect behaviors, you will need to capture the 3xx response codes and ensure a new request is made to the redirect destination.Credits
This vulnerability was discovered and disclosed by the following individuals.
Dennis Brinkrolf, Haxolot (https://haxolot.com/) Tobias Funke, (tobiasfunke93@gmail.com)
CVE-2024-35195
When making requests through a Requests
Session, if the first request is made withverify=Falseto disable cert verification, all subsequent requests to the same origin will continue to ignore cert verification regardless of changes to the value ofverify. This behavior will continue for the lifecycle of the connection in the connection pool.Remediation
Any of these options can be used to remediate the current issue, we highly recommend upgrading as the preferred mitigation.
requests>=2.32.0.requests<2.32.0, avoid settingverify=Falsefor the first request to a host while using a Requests Session.requests<2.32.0, callclose()onSessionobjects to clear existing connections ifverify=Falseis used.Related Links
Release Notes
psf/requests (requests)
### [`v2.32.2`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2322-2024-05-21) [Compare Source](https://togithub.com/psf/requests/compare/v2.32.1...v2.32.2) **Deprecations** - To provide a more stable migration for custom HTTPAdapters impacted by the CVE changes in 2.32.0, we've renamed `_get_connection` to a new public API, `get_connection_with_tls_context`. Existing custom HTTPAdapters will need to migrate their code to use this new API. `get_connection` is considered deprecated in all versions of Requests>=2.32.0. A minimal (2-line) example has been provided in the linked PR to ease migration, but we strongly urge users to evaluate if their custom adapter is subject to the same issue described in CVE-2024-35195. ([#6710](https://togithub.com/psf/requests/issues/6710)) ### [`v2.32.1`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2321-2024-05-20) [Compare Source](https://togithub.com/psf/requests/compare/v2.32.0...v2.32.1) **Bugfixes** - Add missing test certs to the sdist distributed on PyPI. ### [`v2.32.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2320-2024-05-20) [Compare Source](https://togithub.com/psf/requests/compare/v2.31.0...v2.32.0) **Security** - Fixed an issue where setting `verify=False` on the first request from a Session will cause subsequent requests to the *same origin* to also ignore cert verification, regardless of the value of `verify`. (https://github.com/psf/requests/security/advisories/GHSA-9wx4-h78v-vm56) **Improvements** - `verify=True` now reuses a global SSLContext which should improve request time variance between first and subsequent requests. It should also minimize certificate load time on Windows systems when using a Python version built with OpenSSL 3.x. ([#6667](https://togithub.com/psf/requests/issues/6667)) - Requests now supports optional use of character detection (`chardet` or `charset_normalizer`) when repackaged or vendored. This enables `pip` and other projects to minimize their vendoring surface area. The `Response.text()` and `apparent_encoding` APIs will default to `utf-8` if neither library is present. ([#6702](https://togithub.com/psf/requests/issues/6702)) **Bugfixes** - Fixed bug in length detection where emoji length was incorrectly calculated in the request content-length. ([#6589](https://togithub.com/psf/requests/issues/6589)) - Fixed deserialization bug in JSONDecodeError. ([#6629](https://togithub.com/psf/requests/issues/6629)) - Fixed bug where an extra leading `/` (path separator) could lead urllib3 to unnecessarily reparse the request URI. ([#6644](https://togithub.com/psf/requests/issues/6644)) **Deprecations** - Requests has officially added support for CPython 3.12 ([#6503](https://togithub.com/psf/requests/issues/6503)) - Requests has officially added support for PyPy 3.9 and 3.10 ([#6641](https://togithub.com/psf/requests/issues/6641)) - Requests has officially dropped support for CPython 3.7 ([#6642](https://togithub.com/psf/requests/issues/6642)) - Requests has officially dropped support for PyPy 3.7 and 3.8 ([#6641](https://togithub.com/psf/requests/issues/6641)) **Documentation** - Various typo fixes and doc improvements. **Packaging** - Requests has started adopting some modern packaging practices. The source files for the projects (formerly `requests`) is now located in `src/requests` in the Requests sdist. ([#6506](https://togithub.com/psf/requests/issues/6506)) - Starting in Requests 2.33.0, Requests will migrate to a PEP 517 build system using `hatchling`. This should not impact the average user, but extremely old versions of packaging utilities may have issues with the new packaging format. ### [`v2.31.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2310-2023-05-22) [Compare Source](https://togithub.com/psf/requests/compare/v2.30.0...v2.31.0) **Security** - Versions of Requests between v2.3.0 and v2.30.0 are vulnerable to potential forwarding of `Proxy-Authorization` headers to destination servers when following HTTPS redirects. When proxies are defined with user info (`https://user:pass@proxy:8080`), Requests will construct a `Proxy-Authorization` header that is attached to the request to authenticate with the proxy. In cases where Requests receives a redirect response, it previously reattached the `Proxy-Authorization` header incorrectly, resulting in the value being sent through the tunneled connection to the destination server. Users who rely on defining their proxy credentials in the URL are *strongly* encouraged to upgrade to Requests 2.31.0+ to prevent unintentional leakage and rotate their proxy credentials once the change has been fully deployed. Users who do not use a proxy or do not supply their proxy credentials through the user information portion of their proxy URL are not subject to this vulnerability. Full details can be read in our [Github Security Advisory](https://togithub.com/psf/requests/security/advisories/GHSA-j8r2-6x86-q33q) and [CVE-2023-32681](https://nvd.nist.gov/vuln/detail/CVE-2023-32681). ### [`v2.30.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2300-2023-05-03) [Compare Source](https://togithub.com/psf/requests/compare/v2.29.0...v2.30.0) **Dependencies** - ⚠️ Added support for urllib3 2.0. ⚠️ This may contain minor breaking changes so we advise careful testing and reviewing https://urllib3.readthedocs.io/en/latest/v2-migration-guide.html prior to upgrading. Users who wish to stay on urllib3 1.x can pin to `urllib3<2`. ### [`v2.29.0`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2290-2023-04-26) [Compare Source](https://togithub.com/psf/requests/compare/v2.28.2...v2.29.0) **Improvements** - Requests now defers chunked requests to the urllib3 implementation to improve standardization. ([#6226](https://togithub.com/psf/requests/issues/6226)) - Requests relaxes header component requirements to support bytes/str subclasses. ([#6356](https://togithub.com/psf/requests/issues/6356)) ### [`v2.28.2`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2282-2023-01-12) [Compare Source](https://togithub.com/psf/requests/compare/v2.28.1...v2.28.2) **Dependencies** - Requests now supports charset_normalizer 3.x. ([#6261](https://togithub.com/psf/requests/issues/6261)) **Bugfixes** - Updated MissingSchema exception to suggest https scheme rather than http. ([#6188](https://togithub.com/psf/requests/issues/6188)) ### [`v2.28.1`](https://togithub.com/psf/requests/blob/HEAD/HISTORY.md#2281-2022-06-29) [Compare Source](https://togithub.com/psf/requests/compare/v2.28.0...v2.28.1) **Improvements** - Speed optimization in `iter_content` with transition to `yield from`. ([#6170](https://togithub.com/psf/requests/issues/6170)) **Dependencies** - Added support for chardet 5.0.0 ([#6179](https://togithub.com/psf/requests/issues/6179)) - Added support for charset-normalizer 2.1.0 ([#6169](https://togithub.com/psf/requests/issues/6169))Configuration
📅 Schedule: Branch creation - "" (UTC), Automerge - At any time (no schedule defined).
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🔕 Ignore: Close this PR and you won't be reminded about this update again.
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