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CVE-2026-39832

Invoking agent constraints dropped when forwarding keys in golang.org/x/crypto/ssh/agent

Published: May 22, 2026Updated: May 28, 2026 Sources: CVE List NVDCWE-502
NVD MITRE
9.1CVSSCRITICAL
EPSS Score
0.3%
Top 75.5%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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 Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-502

Affected Products

golang.org/x/crypto/ssh/agentgolang.org/x/crypto
Library
OSS Libraries / go
cryptogolangOSS Libraries
golang.org/x/cryptooss-projectOSS Librariesaka x/crypto, golang x crypto
golangoss-projectUSOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

3 techniques
Execution
Initial Access
View detailed technique mapping

References

https://go.dev/issue/79435
go.dev
https://go.dev/cl/778642
go.dev
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
groups.google.com
and 1 more references View all →

Timeline

Published
May 22, 2026
Last Updated
May 28, 2026

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