Description
A malicious X server could send malformed RECORD EnableContext reolies that can cause a X client using the parse_reply_call_callback function in libXtst before 1.2.6 to enter a endless loop.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| X.org | libXtst | < 1.2.6 | 1.2.6 |
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 | libxtst | 2:1.2.6-1 | — |
| Debian 13 | libxtst | No fix yet | — |
| Debian 12 | libxtst | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libxtst | No fix yet | — |
| Ubuntu 26.04 LTS | libxtst | No fix yet | — |
| Ubuntu 24.04 LTS | libxtst | No fix yet | — |
| Ubuntu 22.04 LTS | libxtst | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | libxtst | No fix yet | — |
| Ubuntu Pro 18.04 LTS | libxtst | No fix yet | — |
| Ubuntu Pro 16.04 LTS | libxtst | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | libXtst +1 | 1.2.5-5.3.hum1 | RHSA-2026:93594 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libXtst | 1.2.5-3.1 | openSUSE-SU-2026:12155-1 |
| openSUSE Leap 16.1 | libXtst | 1.2.5-160100.3.1 | openSUSE-SU-2026:22289-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libxtst | 1.2.6-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libXtst | 1.2.6-1 | — |
Advisories 3
- openSUSE-SU-2026:22289-1 Security update for libXtst SUSE / openSUSE Security Updates · Nov 14, 2026
- RHSA-2026:93594 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- openSUSE-SU-2026:12155-1 libXtst-devel-1.2.5-3.1 on GA media SUSE / openSUSE Security Updates · Oct 17, 2026