The golang.org/x/crypto/ssh package contained a vulnerability (CVE-2026-39829) due to lack of enforcement of size limits on RSA and DSA public key parameters. Attackers could supply crafted public keys with very large moduli or DSA parameters, causing inefficient CPU computation that could last several minutes during signature verification. This vulnerability affects the public key authentication process and can be triggered without authentication. The remediation involves imposing an 8192-bit limit on RSA moduli and validating DSA parameters per FIPS 186-2.

An attacker can cause significant CPU resource consumption on a server using the vulnerable golang.org/x/crypto/ssh package by sending crafted public keys with oversized parameters during authentication. This results in a denial-of-service condition due to inefficient computation. There is no indication of code execution or data compromise from the provided data.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The description notes that RSA moduli are now limited to 8192 bits and DSA parameters validated per FIPS 186-2, indicating a fix is planned or implemented. Until an official patch is confirmed, monitor vendor advisories for updates and consider limiting exposure to unauthenticated public key authentication attempts if possible.