What’s Vulnerable › Vulnerabilities

CVE-2026-111943: Distrust compromised intermediate certificates in crypto/x509

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-30
• Weakness: CWE-299

Description

On most platforms, Go uses the given system root certificates. However, in some narrower cases, the system trust stores may not be updated without further action. To defend against the narrower set of cases that may remain affected, a denylist was added in crypto/x509 to return an error when calling Verify with any of the known intermediate certificates that are no longer considered to be trustworthy.

Affected products

• Go Stdlib: before 1.26.10; from 1.27.0-0 before 1.27.3 — fixed in 1.26.10, 1.27.3
• Go standard library crypto/x509: before 1.26.10; from 1.27.0-0 before 1.27.3 — fixed in 1.26.10, 1.27.3

How to fix

Upgrade to a fixed version: Go Stdlib 1.26.10, 1.27.3; Go standard library crypto/x509 1.26.10, 1.27.3. Check the vendor advisory for mitigations.

References

• https://go.dev/cl/851047
• https://go.dev/issue/82345
• https://groups.google.com/g/golang-announce/c/66pojueaQek
• https://pkg.go.dev/vuln/GO-2026-6809
• http://www.openwall.com/lists/oss-security/2026/10/20/29

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