CVE-2021-31523: The Debian xscreensaver 5.42+dfsg1-1 package for XScreenSaver has cap_net_raw enabled for the /usr/libexec/xsc

Routine

HIGH 7.8WATCHLISTMITIGATE

CVE-2021-31523 is a high-severity flaw (CVSS 7.8) affecting xscreensaver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-269
Published	2021-04-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: xscreensaver project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-04-21 19:15 UTCPublished CVE record published
2026-06-17 03:51 UTCUpdated Record last modified

xscreensaver project xscreensaver MITIGATE

Affected: 5.42\+dfsg1-1

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy xscreensaver || rpm -q xscreensaver || xscreensaver --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-31523?

xscreensaver: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-31523 being exploited?

CVE-2021-31523 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-31523 affect?

CVE-2021-31523 affects xscreensaver. Severity is high (CVSS 7.8). 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 Mes

How urgent is CVE-2021-31523?

Priority 39/100. High severity; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2021-34557 MEDIUM 4.6 DOWNGRADE MITIGATE XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs
CVE-2015-8025 LOW 2.1 MITIGATE DOWNGRADE driver/subprocs.c in XScreenSaver before 5.34 does not properly perform an internal consistency check, which a
CVE-2011-2187 HIGH 7.8 UPGRADE MITIGATE xscreensaver before 5.14 crashes during activation and leaves the screen unlocked when in Blank Only Mode and

References

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