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CVE-2026-115557

Distrust compromised intermediate certificates in ssl module

CVSS score

9.4

EPSS probability

—

Risk score

0.9

Published

3 h ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Official patch verified

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Vulnerability description

DayBreach AI Explanation

Verified against sources

CVE-2026-115557 Critical Certificate Security Vulnerability in Python ssl Module

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

A critical vulnerability affects versions of the Python CPython ssl module that lack a denylist mechanism for known compromised certificates.

Why does it matter?

This vulnerability can lead to high-risk confidentiality and integrity losses by failing to automatically reject compromised certificates regardless of the SSLContext policy configuration.

What should be done?

  • Follow vendor advisories
  • Review provided patch references
  • Update Python version
Chain of evidence and sources2 verified claims

Python CPython ssl modülü, bilinen ele geçirilmiş sertifikalara karşı yasaklı liste mekanizması eksikliği nedeniyle etkilenmektedir.

S0 · daybreach-canonicalS1 · cvelist

Yama durumu için sağlanan referanslar ve doğrulanmış yama kanıtları mevcuttur.

S0 · daybreach-canonicalS1 · cvelist
Show the technical text from the sources

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.

CVSS vector: 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

CWE: CWE-299

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-115557 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1Python Software FoundationCPython View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.4CVSS V4_0CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:HCVE CNA
9.4CVSS V40CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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:XNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

CNA çözüm referansı

Open source
reference

Yama veya çözüm referansı

Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-115557 is associated with the following CWEs:

CWE-299: Common Weakness Enumeration Entry CWE-299

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-115557 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
User—

Official Sources and Advisories

http://www.openwall.com/lists/oss-security/2026/10/20/29vendor-advisoryhttps://github.com/python/cpython/pull/160042patchhttps://github.com/python/cpython/issues/160040vendor-advisoryhttps://emudhra.we-have-a-problem.com/vendor-advisoryhttps://mail.python.org/archives/list/security-announce@python.org/thread/FNAJMZV6XQYLVPABNINDMF3VF66AYLW4/vendor-advisory

CVSS Vector Radar Chart

9.4 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.RequiredConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

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
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionP
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)P
Availability (Erişilebilirlik)High

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

PS
Python Software Foundation logo
Python Software Foundation

Weakness Type (CWE & CAPEC)

CWE-299

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CVE-2026-115557 · Distrust compromised intermediate…