Auth bypass in Openbsd

CVE-2019-19521

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).

Vulnerability class: Broken Authentication

EPSS: 0.027 (84.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

  • Openbsd — versions 6.6
  • N/a — versions n/a

Weakness classification (CWE)

Public proof-of-concept exploits

References

  • cve@mitre.org (Exploit, Mailing List, Third Party Advisory, x_refsource_MISC)
  • cve@mitre.org (x_refsource_MISC, Vendor Advisory)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List)
  • cve@mitre.org (mailing-list, x_refsource_MLIST, Exploit, Mailing List, Third Party Advisory)
  • cve@mitre.org (mailing-list, Exploit, x_refsource_BUGTRAQ, Mailing List, Third Party Advisory)
  • cve@mitre.org (Third Party Advisory, x_refsource_MISC)
  • cve@mitre.org (mailing-list, x_refsource_FULLDISC, Third Party Advisory)

Frequently asked questions

What is CVE-2019-19521?
CVE-2019-19521 is a critical-severity vulnerability in Openbsd, classified under Improper Authentication. CVSS score: 9.8/10. Published 2019-12-05.
How severe is CVE-2019-19521?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2019-19521 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.