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Incorrect Default PermissionsWeakness · CWE-276

CVE-2025-46803

MEDIUM · 5.0 CVSS v3.1 Published 2025-05-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
50/100
Remediation priority · Moderate

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The default mode of pseudo terminals (PTYs) allocated by Screen was changed from 0620 to 0622, thereby allowing anyone to write to any Screen PTYs in the system.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Screen's default PTY permissions were changed from 0620 (owner read/write, group write only) to 0622 (owner read/write, group write, others write), allowing any user on the system to write to Screen-allocated pseudo terminals. This exposes session data and could enable injection of commands into active Screen sessions.

MitigationUpdate Screen to the patched version that reverts or corrects the PTY default permissions, or configure Screen to use stricter PTY permissions via the 'defshell' or 'shell' settings.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Screen version
    Run 'screen --version' or 'screen -v' to display the Screen version number
    Affected if The installed version contains the permission change to 0622 (no version specified; compare to any patched version that reverts this default)
  2. Locate active Screen sessions and their PTY devices
    Run 'ls -la /dev/pts/*' while Screen sessions are active to list pseudo terminal device permissions
    Affected if Any PTY device shows permissions 0622 (owner read/write, group write, others write) instead of 0620 (owner read/write, group write only)
  3. Check Screen configuration for PTY permission settings
    Run 'screen -ls' to list active sessions, then inspect any '.screenrc' or '/etc/screenrc' for 'shell', 'defshell', or 'ptypath' directives that control PTY creation
    Affected if No restrictive PTY permission configuration exists and PTY devices created by Screen show 0622 permissions
  4. Verify PTY ownership allows only intended access
    Run 'ls -la /dev/pts/' to confirm PTY devices are not world-writable
    Affected if PTy devices are writable by 'others' (permission bit 2 set in octal 0622)

If Screen is running with default PTY permissions of 0622 (world-writable), any unprivileged user can write to active Screen sessions, exposing session data or enabling command injection.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Screen to the patched version that reverts or corrects the PTY default permissions, or configure Screen to use stricter PTY permissions via the 'defshell' or 'shell' settings.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-46803 in production — separate from our analysis above.

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What this is

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