CVE-2025-23395Public exploit

Local root escalation via privileged logfile reopen

Published May 26, 2025 · Updated May 27, 2025

Privilege dropping errors in GNU Screen 5.0.0 allow local users to gain root privileges when Screen is installed setuid-root. The logfile_reopen() path reopens a user-selected log file with effective root privileges after the user unlinks it or changes its size, allowing a symlink to redirect PTY output into a privileged file. A local account and a setuid-root Screen binary are required; successful exploitation permits arbitrary root-owned file creation or append operations that can lead to root access.

CVSS severity7.3
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege dropping errors in GNU Screen 5.0.0 allow local users to gain root privileges when Screen is installed setuid-root. The logfile_reopen() path reopens a user-selected log file with effective root privileges after the user unlinks it or changes its size, allowing a symlink to redirect PTY output into a privileged file. A local account and a setuid-root Screen binary are required; successful exploitation permits arbitrary root-owned file creation or append operations that can lead to root access.

The record

CVE
CVE-2025-23395
Published
May 26, 2025
Updated
May 27, 2025
Vendor
The GnuPG Project
Product
GNU Screen
Classifications
CWE-271, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 26, 2025CVE publishedPublication date reported by the CVE source.
  2. May 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.0 <=5.0.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The GnuPG Project · GNU Screenversion=5.0 <=5.0.0

Published CVSS scores

7.8SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3SUSECVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-271Privilege Dropping / Lowering Errors
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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