CVE-2026-115557

EUVD-2026-109299
Python has added a denylist for known compromised certificates to the "ssl" module to ensure user safety even without certificate revocation configured. Known compromised certificates will automatically be rejected regardless of the SSLContext policy configuration.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
PSFCNA
9.4 CRITICAL
NETWORK
LOW
NONE
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
pythoncpython
𝑥
≤ 3.16.0
CNA
Common Weakness Enumeration
References
http://www.openwall.com/lists/oss-security/2026/10/20/29
https://emudhra.we-have-a-problem.com/
https://github.com/python/cpython/issues/160040
https://github.com/python/cpython/pull/160042
https://mail.python.org/archives/list/security-announce@python.org/thread/FNAJMZV6XQYLVPABNINDMF3VF66AYLW4/
http://www.openwall.com/lists/oss-security/2026/10/24/5