CVE-2026-124249
`http.cookiejar` applies expired `Set-Cookie` to cookie store before policy validation
http.cookiejar.CookieJar deleted a stored cookie when a response carried an already expired Set-Cookie header for it, using the Domain and Path attributes from the header without consulting the cookie policy. A server could therefore delete cookies belonging to other domains from a shared cookie jar, such as the one used by urllib's HTTPCookieProcessor. The fix consults the cookie policy before an expired cookie may delete an existing one, as required by RFC 6265 section 5.3.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: PSFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: PSFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: PSFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: PSFAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| CPython Python Software Foundation |
≥ 0; < 3.16.0 (affected, python)
Other versions: unaffected |
CNA: PSF |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 6.3 medium |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | CNA: PSF |
| 4.0 / 6.3 medium |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/python/cpython/pull/161570CNA: PSF · patch
- https://github.com/python/cpython/issues/161569CNA: PSF · issue-tracking
- https://mail.python.org/archives/list/[email protected]/thread/Y6IKNZ2VZUS2L6CLQICSFUEMCLT7OLTY/CNA: PSF · vendor-advisory
- https://github.com/python/cpython/commit/4e9d037f1cfc8e29efcb1f67bc668e06ff2b6643CNA: PSF · patch
- https://github.com/python/cpython/commit/8eb3d2c1c41ca7ce628554413981c1eb763a1494CNA: PSF · patch
- https://github.com/python/cpython/commit/ac1d49f4fbb33941475c5aa3cb663ab39d64cb73CNA: PSF · patch
- http://www.openwall.com/lists/oss-security/2026/11/09/24ADP: CVE
- https://github.com/python/cpython/issues/161569[email protected]
- https://github.com/python/cpython/pull/161570[email protected]
- https://mail.python.org/archives/list/[email protected]/thread/Y6IKNZ2VZUS2L6CLQICSFUEMCLT7OLTY/[email protected]
- http://www.openwall.com/lists/oss-security/2026/11/09/24af854a3a-2127-422b-91ae-364da2661108
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