Description
pam-krb5 before 4.9 has a buffer overflow that might cause remote code execution in situations involving supplemental prompting by a Kerberos library. It may overflow a buffer provided by the underlying Kerberos library by a single '\0' byte if an attacker responds to a prompt with an answer of a carefully chosen length. The effect may range from heap corruption to stack corruption depending on the structure of the underlying Kerberos library, with unknown effects but possibly including code execution. This code path is not used for normal authentication, but only when the Kerberos library does supplemental prompting, such as with PKINIT or when using the non-standard no_prompt PAM configuration option.
References (6)
Core 6
Core References
Patch, Third Party Advisory x_refsource_confirm
https://github.com/rra/pam-krb5/commit/e7879e27a37119fad4faf133a9f70bdcdc75d760
Mailing List, Patch, Third Party Advisory x_refsource_confirm
http://www.openwall.com/lists/oss-security/2020/03/31/1
Third Party Advisory vendor-advisory
x_refsource_debian
https://www.debian.org/security/2020/dsa-4648
Mailing List, Third Party Advisory mailing-list
x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2020/04/msg00000.html
Vendor Advisory vendor-advisory
x_refsource_ubuntu
https://usn.ubuntu.com/4314-1/
Various Sources x_refsource_misc
https://www.eyrie.org/~eagle/software/pam-krb5/security/2020-03-30.html
Scores
CVSS v3
9.8
EPSS
0.0730
EPSS Percentile
91.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Details
CWE
CWE-120
Status
published
Products (4)
debian/debian_linux
8.0
debian/debian_linux
9.0
debian/debian_linux
10.0
pam-krb5_project/pam-krb5
< 4.9
Published
Mar 31, 2020
Tracked Since
Feb 18, 2026