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NVD / CVE Program· CNA mitre

CVE-2023-24626: 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 loca

Noroxi assessment

Priority: Monitor (action score 26/100)

  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.54% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: cbl2 screen 4.9.1-1 on CBL Mariner 2.0 4.9.1-1.

Low priority for now. Upgrade to cbl2 screen 4.9.1-1 on CBL Mariner 2.0 4.9.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.5 · v3.1—Proof of concept Fix available
Published
Apr 8, 2023
Updated
Jun 17, 2026
EPSS
0.5% · 45th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-24626

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
gnuscreen

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • gnu screenup to 4.9.0 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.15screenbefore 4.8.0-r64.8.0-r6
Alpine:v3.16screenbefore 4.9.0-r14.9.0-r1
Alpine:v3.18screenbefore 4.9.0-r34.9.0-r3
Debian:12screenfrom 0—
Debian:13screenbefore 4.9.1-14.9.1-1
openSUSE:Tumbleweedscreenbefore 4.9.1-1.14.9.1-1.1

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-26937encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of service (invalid write access and application crash) or
    42Plan
  • CVE-2003-0972Integer signedness error in ansi.c for GNU screen 4.0.1 and earlier, and 3.9.15 and earlier, allows local users to execute arbitrary code vi
    41Plan
  • CVE-2020-9366A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49.
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2007-3048Jun 5, 2007 · GNU screen 4.0.3 allows local users to unlock the screen via a CTRL-C sequence at the password prompt.
    28Monitor
  • ← EarlierCVE-2009-1214Apr 1, 2009 · GNU screen 4.0.3 creates the /tmp/screen-exchange temporary file with world-readable permissions, which might allow local users to obtain se
    19Monitor
  • ← EarlierCVE-2017-5618Mar 20, 2017 · GNU screen before 4.5.1 allows local users to modify arbitrary files and consequently gain root privileges by leveraging improper checking o
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
cbl2 screen 4.9.1-1 on CBL Mariner 2.04.9.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
alpine:screen4.8.0-r6 · Alpine:v3.15Package registry (OSV)
debian:screen4.9.1-1 · Debian:13Package registry (OSV)
opensuse:screen4.9.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrylocal2023-04-05

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-3 d
  2. Published
  3. TodayNov 8, 2026+1310 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-732 · Incorrect Permission Assignment for Critical Resource

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records