Description
The LockServer function in os/utils.c in X.Org xserver before 1.11.2 allows local users to change the permissions of arbitrary files to 444, read those files, and possibly cause a denial of service (removed execution permission) via a symlink attack on a temporary lock file.
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 | xorg-server | 2:1.11.1.901-2 | — |
| Debian 13 | xorg-server | 2:1.11.1.901-2 | — |
| Debian 12 | xorg-server | 2:1.11.1.901-2 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | xorg-x11-server +8 | 1.10.6-1.el6 | RHSA-2012:0939 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- X.Org xorg 1.4 < 1.11.2 - File Permission Change EDB-18040 · local · Oct 28, 2011
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- RHSA-2012:0939 Red Hat Security Advisory: xorg-x11-server security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
References
- [xorg] 20111018 X.Org security advisory: xserver locking code issues mailing-list
- http://cgit.freedesktop.org/xorg/xserver/commit/?id=b67581cf825940fdf52bf2e0af4330e695d724a4
- 46460 third-party-advisory
- RHSA-2012:0939 vendor-advisory
- 49579 third-party-advisory