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Security Digest · Vulnerability record

CVE-2026-42508: golang.org/x/crypto vulnerable to auth bypass via unenforced @revoked status

Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation.

CVSS 7.4 High EPSS 0.7% · p51

Updated By erroneo.us Security Desk53 references Seen in the digest for Jun 25, 2026

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

  • No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
  • EPSS 0.7%, percentile 51: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 51% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
  • Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
  • Only applies if your dependency tree includes golang.org/x/crypto (Go) < 0.52.0, fixed in 0.52.0. Check your lockfile, including transitive dependencies.

What it is

Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.

From the GitHub advisory

Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.

Weakness type: CWE-295.

Product: golang.org/x/crypto (Go) · Assigned by: Go · Published: 2026-05-22

Affected and fixed versions

EcosystemPackageVulnerableFirst fixed
Gogolang.org/x/crypto< 0.52.00.52.0
VendorProductAffected versions (per CVE record)
golang.org/x/cryptogolang.org/x/crypto/ssh/knownhosts< 0.52.0

Severity scores

Scored byCVSSScoreVector
CISA-ADP3.19.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
redhat-SADP3.17.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
GitHub3.19.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
  • Attack vector: network (remotely reachable)
  • Attack complexity: high (needs special conditions)
  • Privileges required: none (no login)
  • User interaction: none
  • Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

  • CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
  • CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
  • FIRST EPSS (model of 2026-10-21): 0.65% probability of exploitation activity in the next 30 days; percentile 51.

Timeline

  • — CVE record published by Go
  • — GitHub-reviewed advisory GHSA-5cgq-3rg8-m6cv published (critical)
  • — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

  1. access.redhat.com access.redhat.com
  2. access.redhat.com access.redhat.com
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Vulnerability records

  1. GitHub Advisory GHSA-5cgq-3rg8-m6cv github.com
  2. CVE.org record CVE-2026-42508 cve.org
  3. NVD entry CVE-2026-42508 nvd.nist.gov

Other references from the CVE record and advisory

  1. go.dev go.dev
  2. go.dev go.dev
  3. groups.google.com groups.google.com
  4. pkg.go.dev pkg.go.dev
  5. access.redhat.com access.redhat.com
  6. RHBZ#2480688 bugzilla.redhat.com
  7. security.access.redhat.com security.access.redhat.com
  8. access.redhat.com access.redhat.com

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