CVE-2019-19521 Auth bypass in n/a

Critical 9.8 Published 4 Dec 2019 Updated 5 Aug 2024

Attackers can bypass authentication in OpenBSD services like smtpd and ldapd by using the -schallenge username due to a flaw in libc.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2019-19521?

CVE-2019-19521 is a critical authentication bypass vulnerability in Openbsd Openbsd, published on 4 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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).

Weakness: CWE-287

Which versions are affected by CVE-2019-19521?

It affects 1 product.

Products include Openbsd Openbsd.

How do I fix CVE-2019-19521?

No fix has been published for CVE-2019-19521 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2019-19521 being exploited?

There is no known exploitation of CVE-2019-19521 in the wild and no public exploit code.

All Openbsd Openbsd vulnerabilities

Sources

Also known as GHSA-gw7q-976q-g767.