CVE-2026-115557

CRITICAL 9.4CVE-2026-115557 · Published 24/10/2026 · updated 27/10/2026

In short

CVE-2026-115557 is a CRITICAL (CVSS 9.4) vulnerability.
Chance of exploitation in the next 30 days (EPSS): 0.53%, higher than 45.1% of all vulnerabilities.
No patched version is listed yet: follow the vendor's advisory in References.

Package	Affected versions	Patched versions
—	No affected product versions are listed for this vulnerability yet.

Description

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.

References

openwall.com/lists/oss-security/2026/10/20/29
emudhra.we-have-a-problem.com
python/cpython commit 21a5089
python/cpython commit 36cd295
python/cpython commit 48d9b27
python/cpython commit 7dd8b47
python/cpython commit 98f0e4e
python/cpython commit a17d9ef
python/cpython commit af52b41
python/cpython commit c7fd7ed
python/cpython commit e2a9dd9
python/cpython commit e4500d8

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