CVE-2026-124249 `http.cookiejar` applies expired `Set-Cookie` to cookie store before policy validation
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-124249?
CVE-2026-124249 is a medium-severity vulnerability in CPython, published on 9 Nov 2026.
Official description
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.
Weakness: CWE-346
Which versions are affected by CVE-2026-124249?
How do I fix CVE-2026-124249?
No fix has been published for CVE-2026-124249 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-124249 being exploited?
There is no known exploitation of CVE-2026-124249 in the wild and no public exploit code.
Sources
Also known as AZL-112910, AZL-112916, GHSA-chc2-vx2q-cwqf, UBUNTU-CVE-2026-124249.