Description
The _expand_arg function in the pam_env module (modules/pam_env/pam_env.c) in Linux-PAM (aka pam) before 1.1.5 does not properly handle when environment variable expansion can overflow, which allows local users to cause a denial of service (CPU consumption).
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pam | 1.1.3-5 | — |
| Debian 13 | pam | 1.1.3-5 | — |
| Debian 12 | pam | 1.1.3-5 | — |
| Debian 6.0 | pam | 1.1.1-6.1+squeeze1 | DSA-2326-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | pam +1 | 1.1.1-13.el6 | RHSA-2013:0521 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | pam | 1.3.0-3.4 | openSUSE-SU-2024:10405-1 |
Advisories 3
- RHSA-2013:0521 Red Hat Security Advisory: pam security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-2326-1 pam - several Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10405-1 pam-1.3.0-3.4 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- GLSA-201206-31 vendor-advisory
- USN-1237-1 vendor-advisory
- 46583 third-party-advisory
- 49711 third-party-advisory
- https://bugs.launchpad.net/ubuntu/+source/pam/+bug/874565
- http://git.fedorahosted.org/git/?p=linux-pam.git%3Ba=commitdiff%3Bh=109823cb621c900c07c4b6cdc99070d354d19444