ssh-keygen in OpenSSH before 10.6 incorrectly calculates certificate expiration times due to daylight saving time mishandling. This flaw causes certificates to appear valid beyond their intended lapse, extending authentication privileges. The weakness corresponds to CWE‑193 and CWE‑295, indicating an incorrect calculation of time values and an insecure method for certificate validation or generation.

All OpenBSD OpenSSH installations running a version earlier than 10.6 are affected. The product has no explicit version list in the CVE data; the description indicates a pre‑10.6 vulnerability, and users in certain Antarctic regions may see a slightly more severe effect.

The CVSS score is 2.5, classifying the flaw as low severity. EPSS is less than 1% and the issue is not in the CISA KEV catalog, so exploitation likelihood is limited. Attackers would need the ability to create or influence certificates through ssh-keygen, with impact limited to authentication validity rather than immediate remote code execution or data compromise. The potential for extended validity poses a trickle‑down risk to account compromise over time.