Vulnary
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Critical· 9.1official fix available

CVE-2026-42508

A critical flaw in Go’s crypto library let attackers use a revoked certificate key because the library didn’t check revocation properly. The issue was fixed by adding checks for both the key and its signature key. Users should update to a patched version.

publishedMay 22, 2026
last modifiedAug 4, 2026
sourcesNVD
severity · cvss
9.1
critical · how bad it is
exploitation · epss
<1%
44th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 18, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

The Go programming language’s crypto package, used in many Go applications, is affected. Developers and users of Go applications that rely on the crypto library should ensure they are running a patched version.

02

Real-world impact

An attacker could use a revoked key to forge signatures or impersonate a trusted party, potentially gaining unauthorized access or tampering with data.

03

Why this severity

The CVSS score of 9.1 reflects that the vulnerability can be exploited remotely with no authentication or user interaction, and it can compromise confidentiality and integrity of data.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade golang crypto to a version that includes the revocation check.

NVD description indicates the fix was applied.

05

Timeline

  1. May 22, 2026 · May 22, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 19, 2026 · 17d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
  3. Aug 4, 2026 · 7h ago
    Advisory updated
    The NVD record was last revised.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactNone
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →