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VulnerabilityPublished Updated

CVE-2026-39835: golang.org/x/crypto/ssh · NULL Pointer Dereference

Affects golang.org/x/crypto/sshSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 0.52.0 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.52.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade golang.org/x/crypto/ssh to 0.52.0.

Affected software

ProductAffectedFixed in
golang.org/x/cryptogolang.org/x/crypto/sshAffected
  • <0.52.0
Fixed in
  • 0.52.0
Gogolang.org/x/crypto/sshpkg:golang/golang.org/x/crypto/sshOther threatsAffected
  • =0
Fixed in–
Gogolang.org/x/crypto/sshpkg:golang/golang.org/x/crypto/sshOther threatsAffected
  • <0.52.0
Fixed in
  • 0.52.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Currently, no mitigation is available that meets Red Hat's criteria for ease of use, applicability, and stability. Red Hat is working on fixes and will release updates in affected products such as Red Hat Edge Manager. Until then, avoid using CertChecker without explicitly setting IsUserAuthority or IsHostAuthority callbacks if possible.

Description

SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a client presenting a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil.

References

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