CVE-2025-46803
Description
A flaw was found in Screen. The default mode for pseudo-terminals (PTYs) allocated by Screen was changed from 0620 to 0622. This vulnerability allows public writes to any PTYs in the system.
Statement
The change in the default PTY mode from 0620 to 0622 in Screen represents a significant security vulnerability because it directly exposes privileged terminal sessions to unauthorized local modification. In multi-user environments, PTYs act as communication endpoints between user shells and the system, and world-writable PTYs (0622) allow any user on the system to inject arbitrary input into another user’s terminal. Unlike a typical permission misconfiguration that may be considered a moderate flaw, this vulnerability can lead to active session hijacking, command injection, or data corruption in interactive processes like shells, editors, and administrative sessions. As PTYs are foundational to the UNIX security model for user isolation, this vulnerability undermines the integrity of user sessions and can result in privilege escalation when combined with poorly secured scripts or session contexts.
Mitigation
No mitigation is currently available that meets Red Hat Product Security’s standards for usability, deployment, applicability, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.7 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
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