CVE-2026-39833: golang.org/x/crypto/ssh/agent · Improperly Implemented Security Check for Standard
Affects golang.org/x/crypto/ssh/agentSource CVE Database V5
Not known to be exploited · CVSS 9.1 Critical : upgrade to 0.52.0 as a priority.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% 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 29 Oct 2026.
What to do
Upgrade golang.org/x/crypto/ssh/agent to 0.52.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| golang.org/x/cryptogolang.org/x/crypto/ssh/agent | Affected
| Fixed in
|
Gogolang.org/x/crypto/ssh/agentpkg:golang/golang.org/x/crypto/ssh/agentOther threats | Affected
| Fixed in– |
Gogolang.org/x/crypto/ssh/agentpkg:golang/golang.org/x/crypto/ssh/agentOther 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
The vendor has indicated that NewKeyring() now returns an error when unsupported constraints are requested, which suggests a fix is planned or implemented. Users should monitor official golang.org/x/crypto advisories for updates and apply any released patches promptly.
Description
The in-memory keyring returned by NewKeyring() silently accepted keys with the ConfirmBeforeUse constraint but never enforced it. The key would sign without any confirmation prompt, with no indication to the caller that the constraint was not in effect. NewKeyring() now returns an error when unsupported constraints are requested.