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Fencer Vulns
critical 9.8

CVE-2020-10595 json

pam-krb5 before 4.9 has a buffer overflow that might cause remote code execution in situations involving supplemental prompting by a Kerber…

published 2020-03-31 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-3044

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.8%
EPSS 4.8% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

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.

Patch / fix

  • pam-krb5_project pam-krb5 4.9
  • libpam-krb5 Debian 14, Debian 13, Debian 12 4.9-1

debian advisories DEBIAN-CVE-2020-10595

  • libpam-krb5 Ubuntu 16.04 LTS 4.7-2ubuntu0.1
  • libpam-krb5 Ubuntu 18.04 LTS 4.8-1ubuntu0.1
  • libpam-krb5 Ubuntu Pro 14.04 LTS 4.6-2ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2020-10595

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • pam-krb5 Arch Linux 4.9-1

arch linux advisories AVG-1119

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-10595 updated cvss 7.5

pam_krb5: incorrect input handling results in single byte buffer overflow which may lead to heap corruption

  • Red Hat Enterprise Linux 5 pam_krb5 Red Hat Enterprise Linux 6 pam_krb5 Red Hat Enterprise Linux 7 pam_krb5
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.78% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.