November 14, 2026

CVE Watchtower

CVE-2026-124249Python Software Foundation CPython

NVD

Vulnerability Summary

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.
Severity Level
MEDIUM(6.3)
Published Date
Nov 9, 2026
Last Modified
Nov 12, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.27%Probability
Root Weakness (CWE)
CWE-346 β†—
See the MITRE CWE entry for the full definition of this weakness.
CVSS v4.0 Base Metrics — Score 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
Attack VectorNetwork
Attack ComplexityLow
Attack RequirementsPresent
Privileges RequiredNone
User InteractionNone
Confidentiality (Vulnerable System)None
Integrity (Vulnerable System)Low
Availability (Vulnerable System)None
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None

Affected & Patched Versions

Affected Versions
  • Python Software Foundation CPython < 3.16.0a2
Patched Versions
  • Python Software Foundation CPython 3.16.0a2

What to do

Fix it during your normal patch cycle. No exploitation is confirmed yet.

  1. Check whether you run Python Software Foundation CPython and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 9, 2026Published
  • Nov 12, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 14, 2026 00:39 UTC