CVE-2019-19521: OpenBSD

Critical severity, CVSS 9.8. EPSS: 2.7% chance of exploitation in the next 30 days.

libc in OpenBSD 6.6 allows authentication bypass via the -schallenge username, as demonstrated by smtpd, ldapd, or radiusd. This is related to gen/auth_subr.c and gen/authenticate.c in libc (and login/login.c and xenocara/app/xenodm/greeter/verify.c).

Affected products

• OpenBSD OpenBSD: version 6.6 only

Published 2019-12-05. Last modified 2026-06-17.