Description
XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. A buffer overflow in update_screen_layout() allows an attacker to bypass the standard screen lock authentication mechanism by crashing XScreenSaver. The attacker must physically disconnect many video outputs.
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 | xscreensaver | 5.45+dfsg1-2 | — |
| Debian 13 | xscreensaver | 5.45+dfsg1-2 | — |
| Debian 12 | xscreensaver | 5.45+dfsg1-2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | xscreensaver | No fix yet | — |
| Ubuntu 20.04 LTS | xscreensaver | No fix yet | — |
| Ubuntu 18.04 LTS | xscreensaver | No fix yet | — |
| Ubuntu 16.04 LTS | xscreensaver | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | xscreensaver | 5.44-150000.5.6.1 | SUSE-SU-2022:2641-1 |
| SLES 12 SP5 | xscreensaver | 5.22-8.3.1 | SUSE-SU-2022:2642-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP5 | xscreensaver | 5.22-8.3.1 | SUSE-SU-2022:2642-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.3 | xscreensaver | 5.44-150000.5.6.1 | SUSE-SU-2022:2641-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | xscreensaver | 6.02-r0 | — |
| Alpine v3.23 | xscreensaver | 6.02-r0 | — |
| Alpine v3.22 | xscreensaver | 6.02-r0 | — |
| Alpine v3.21 | xscreensaver | 6.02-r0 | — |
| Alpine v3.20 | xscreensaver | 6.02-r0 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | xscreensaver | 6.02-r0 | — |
| Alpine v3.18 | xscreensaver | 6.02-r0 | — |
| Alpine v3.17 | xscreensaver | 6.02-r0 | — |
| Alpine v3.16 | xscreensaver | 6.02-r0 | — |
Advisories 2
- SUSE-SU-2022:2641-1 Security update for xscreensaver SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:2642-1 Security update for xscreensaver SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/QubesOS/qubes-issues/issues/6595
- https://www.openwall.com/lists/oss-security/2021/06/05/1
- https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txt
- https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outputs-info.patch
- [oss-security] 20210611 Re: XScreenSaver 5.45: Disconnecting a video output can cause XScreenSaver to crash and unlock mailing-list
- [oss-security] 20210706 xscreensaver 5.45 crash mailing-list
- FEDORA-2021-5af4452ffd vendor-advisory