CVE-2026-42508: golang.org/x/crypto/ssh/knownhosts · Improper Certificate Validation
Affects golang.org/x/crypto/ssh/knownhostsSource CVE Database V5
Not known to be exploited · CVSS 9.1 Critical : upgrade to 0.52.0 as a priority.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 6.9% chance of exploitation in 30 days – higher than 94% 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:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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/knownhosts to 0.52.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| golang.org/x/cryptogolang.org/x/crypto/ssh/knownhosts | Affected
| Fixed in
|
Gogolang.org/x/crypto/ssh/knownhostspkg:golang/golang.org/x/crypto/ssh/knownhostsOther threats | Affected
| Fixed in– |
Gogolang.org/x/crypto/ssh/knownhostspkg:golang/golang.org/x/crypto/ssh/knownhostsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has issued advisories acknowledging the vulnerability and is working on fixes. Users should monitor the Red Hat advisory pages and apply updates once available. If you cannot patch yet, users should consider mitigating exposure by restricting access to affected systems and monitoring for suspicious activity related to SSH key usage. Consult the vendor advisory for the latest remediation guidance and update instructions.
Description
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.
References
- go.dev/issue/79568 (opens in a new tab)
- go.dev/cl/781220 (opens in a new tab)
- groups.google.com/g/golang-announce/c/a082jnz-LvI (opens in a new tab)
- pkg.go.dev/vuln/GO-2026-5021 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-42508 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2480688 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42508.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:41019 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36796 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37072 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:35833 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37123 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36808 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:43692 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:41064 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47737 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:26546 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:26547 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36651 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:40945 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:40118 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23262 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23264 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36648 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:41036 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37387 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:42146 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:43052 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:42796 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:41066 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:41031 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:40262 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:36797 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:46885 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47735 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:49944 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:51033 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:51288 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:52857 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:52910 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:54400 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:57194 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:59467 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:60520 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:61314 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:65126 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:66521 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:66022 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:67450 (opens in a new tab)