9.1

CVE-2026-39832: Invoking agent constraints dropped when forwarding keys in golang.org/x/crypto/ssh/agent

Modified
AliasesUBUNTU-CVE-2026-39832DEBIAN-CVE-2026-39832CGA-22fv-wv49-9j74
Published 22-05-2026Last modified 15-09-2026

Vulnerability summary

CVE-2026-39832 is a critical (CVSS 9.1) Deserialization of Untrusted Data vulnerability in golang crypto. EPSS estimates a 0.68% chance of exploitation in the next 30 days, higher than 52.5% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.1 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.68%
0%100%
Low · -0.03 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 67 · Related 69
OPENSUSE-SU-2026:10842-1OPENSUSE-SU-2026:10845-1OPENSUSE-SU-2026:10856-1OPENSUSE-SU-2026:10949-1OPENSUSE-SU-2026:11126-1OPENSUSE-SU-2026:11305-1

Timeline

  1. 22-05-2026
    PublishedVulnerability first disclosed.
  2. 15-09-2026
    Last modifiedVulnerability information updated.

Description

When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.68%

Chance of exploitation in the next 30 days

Percentile

53%

Versus all other CVEs

30-day change

Decrease -0.03 pp

From 0.72% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard200 products
  • aactl< 0.4.12-r53
  • act< 0.2.88-r6
  • actions-runner-controllerAll versions (No fix recorded)
  • actions-runner-controller-fipsAll versions (No fix recorded)
  • ageAll versions (No fix recorded)

1 vendor · 200 products · Showing 200 of 2855

References

51 links
Show all 51 references