CVE-2026-39833

A flaw was found in golang.org/x/crypto/ssh/agent. The NewKeyring() function, which creates an in-memory keyring, failed to enforce the ConfirmBeforeUse constraint on keys. This allowed keys configured to require user confirmation before use to perform signing operations without any prompt or indication to the user. Consequently, an attacker could potentially bypass intended security controls, leading to unauthorized cryptographic signing actions.

Red Hat rates this issue as Moderate with RH CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N). A flaw was found in golang.org/x/crypto/ssh/agent where the in-memory keyring returned by NewKeyring() silently accepted SSH agent keys with the ConfirmBeforeUse constraint but did not enforce interactive confirmation before signing. Exploitation requires local access and low privileges on a system where an affected application uses NewKeyring() with ConfirmBeforeUse. Most Red Hat products that bundle golang.org/x/crypto do not use the ssh/agent ConfirmBeforeUse feature in their supported execution paths. The upstream CISA CVSS 9.1 assumes a broader network attack context that does not reflect Red Hat product deployment.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Update affected Go applications to use golang.org/x/crypto version 0.52.0 or later, which rejects unsupported ConfirmBeforeUse keys instead of silently ignoring the constraint. As a workaround, do not add keys with ConfirmBeforeUse to the in-memory keyring from golang.org/x/crypto/ssh/agent, or use an SSH agent implementation that correctly enforces confirm-before-use.