CVE-2023-24626: socket.c in GNU Screen through 4.9.0, when installed setuid or setgid (the default on platforms such as Arch L

Q: How do I fix CVE-2023-24626?

screen: upgrade to newer than 4.9.0. Exact commands for each OS are on this page.

Q: Is CVE-2023-24626 being exploited?

CVE-2023-24626 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-24626 affect?

CVE-2023-24626 affects screen. Severity is medium (CVSS 6.5). socket.c in GNU Screen through 4.9.0, when installed setuid or setgid (the default on platforms such as Arch Linux and FreeBSD), allows local users to send a privileged SIGHUP signal to any PID, causing a denial of service or disruption of

Q: How urgent is CVE-2023-24626?

Priority 39/100. Public exploit reference

Routine

MEDIUM 6.5UPGRADE

CVE-2023-24626 is a medium-severity flaw (CVSS 6.5) affecting screen. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

socket.c in GNU Screen through 4.9.0, when installed setuid or setgid (the default on platforms such as Arch Linux and FreeBSD), allows local users to send a privileged SIGHUP signal to any PID, causing a denial of service or disruption of the target process.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-732
Published	2023-04-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: gnu

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

Am I affected?

Timeline

2023-04-08 05:15 UTCPublished CVE record published
2026-06-17 05:39 UTCUpdated Record last modified

gnu screen UPGRADE

Affected: <= 4.9.0

Fixed in: newer than 4.9.0

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 4.9.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade screen

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade screen

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: GNU screen v4.9.0 - Privilege Escalation

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-2023-24626?

screen: upgrade to newer than 4.9.0. Exact commands for each OS are on this page.

Is CVE-2023-24626 being exploited?

CVE-2023-24626 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-2023-24626 affect?

CVE-2023-24626 affects screen. Severity is medium (CVSS 6.5). socket.c in GNU Screen through 4.9.0, when installed setuid or setgid (the default on platforms such as Arch Linux and FreeBSD), allows local users to send a privileged SIGHUP signal to any PID, causing a denial of service or disruption of

How urgent is CVE-2023-24626?

Priority 39/100. Public exploit reference

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CVE-2020-9366 CRITICAL 9.8 UPGRADE A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49
CVE-2017-5618 HIGH 7.8 UPGRADE GNU screen before 4.5.1 allows local users to modify arbitrary files and consequently gain root privileges by

References

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