What is the CVSS score of CVE-2026-39833?

CVE-2026-39833 has a CVSS 3.1 base score of 9.1 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.0%.

Which versions of golang.org/x/crypto are affected by CVE-2026-39833?

Applications using Go's SSH agent library (golang.org/x/crypto/ssh/agent versions before 0.52.0) that implemented ConfirmBeforeUse controls to gate sensitive SSH key signing operations discover these…. A patch is available.

How to fix or mitigate CVE-2026-39833?

Within 24 hours: Conduct inventory of all Go applications using golang.org/x/crypto/ssh/agent dependency and document current versions in use. Within 7 days: Upgrade golang.org/x/crypto/ssh/agent to version 0.52.0 or later in all affected applications, rebuild, and stage for production deployment. Within 30 days: Deploy all patched applications to production environments and validate SSH authentication workflows with confirmation prompts functioning correctly.

golang.org/x/crypto CVE-2026-39833

EUVD-2026-31389 CRITICAL

Missing Authorization (CWE-862)

2026-05-22 Go

GHSA-jppx-rxg9-jmrx

Authentication Bypass Golang Org X Crypto Ssh Agent Suse

9.1

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.1 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

SUSE

CRITICAL

qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Analysis Generated

May 28, 2026 - 15:07 vuln.today

CVSS changed

May 28, 2026 - 15:07 NVD

9.1 (None) 9.1 (CRITICAL)

Patch available

May 22, 2026 - 04:31 EUVD

CVE Published

May 22, 2026 - 02:31 nvd

UNKNOWN (no severity yet)

DescriptionCVE.org

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.

AnalysisAI

Authentication bypass in Go's golang.org/x/crypto/ssh/agent in-memory keyring (versions before 0.52.0) allows SSH key signing operations to proceed without the intended ConfirmBeforeUse user confirmation prompt. Applications that relied on this constraint to gate sensitive signing actions effectively had no protection, with no error returned to indicate the constraint was silently ignored. No public exploit identified at time of analysis and EPSS is very low (0.02%), but SSVC rates technical impact as total.

Technical ContextAI

The vulnerability lives in the agent.NewKeyring() implementation of the golang.org/x/crypto/ssh/agent package, which provides an in-memory SSH agent keyring used by Go programs that implement or embed an ssh-agent. SSH agent key constraints (RFC 4251 / draft-miller-ssh-agent) allow callers to attach restrictions to a key such as ConfirmBeforeUse, which is supposed to require an out-of-band confirmation before each signing operation. The CPE confirms the affected component is cpe:2.3:a:golang.org/x/crypto:golang.org/x/crypto/ssh/agent. CWE-862 (Missing Authorization) describes the root cause: the keyring accepted the constraint at AddKey time but the Sign path never consulted or enforced it, so the authorization check that callers expected was simply absent.

RemediationAI

Vendor-released patch: upgrade golang.org/x/crypto to 0.52.0 or later (run 'go get golang.org/x/crypto@v0.52.0' and rebuild affected binaries), tracked in the upstream issue at https://go.dev/issue/79436 with fixes in https://go.dev/cl/778640 and https://go.dev/cl/778641 and announced at https://groups.google.com/g/golang-announce/c/a082jnz-LvI. After upgrading, NewKeyring() now returns an error when an unsupported constraint such as ConfirmBeforeUse is requested, so audit calling code to handle that error and either implement confirmation out-of-band or refuse to add the key. Until the upgrade can be deployed, do not rely on ConfirmBeforeUse as a security boundary in the in-memory keyring - instead remove keys requiring confirmation from the keyring, gate signing in the calling application layer, or restrict agent socket exposure to trusted local processes only; the trade-off is loss of per-use confirmation UX that some workflows depend on.