| Name | CVE-2021-31523 |
| Description | The Debian xscreensaver 5.42+dfsg1-1 package for XScreenSaver has cap_net_raw enabled for the /usr/libexec/xscreensaver/sonar file, which allows local users to gain privileges because this is arguably incompatible with the design of the Mesa 3D Graphics library dependency. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 987149 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| xscreensaver (PTS) | buster | 5.42+dfsg1-1 | fixed |
| bullseye | 5.45+dfsg1-2 | fixed |
| bookworm | 6.06+dfsg1-3 | fixed |
| sid, trixie | 6.08+dfsg1-1 | fixed |
The information below is based on the following data on fixed versions.
Notes
[buster] - xscreensaver <not-affected> (Vulnerability introduced later)
[stretch] - xscreensaver <not-affected> (Vulnerability introduced later)
Fixed upstream in 6.00 (no public version control): https://twitter.com/jwz/status/1383503845217554444
https://www.openwall.com/lists/oss-security/2021/04/17/1
https://bugs.chromium.org/p/project-zero/issues/detail?id=2174
Only in 5.44+dfsg1-1 net_raw capability was added to sonar executable via postinst
and so exposing the vulnerability.