CVE-2026-93515
Description
A flaw was found in xorg-x11-server. A use-after-free vulnerability, where the application accesses memory after it has already been released, occurs in the Present extension because window notification entries are not properly unlinked before cleaning up window resources. An authenticated local X client can exploit this flaw by creating cross-window notifications and subsequently destroying the target window. Successful exploitation primarily results in a Denial of Service (DoS) via an X server crash, and may potentially lead to information disclosure.
Statement
This vulnerability is rated as a Moderate impact for Red Hat Enterprise Linux because exploitation requires an established, authenticated local client connection to the display server, preventing unauthenticated remote exploitation. In environments running the X server or Xwayland, a client within an active graphical session can trigger memory corruption by manipulating presentation event notifications across terminating application windows. The primary impact is a display server crash that terminates active user sessions, though limited local information disclosure may also occur.
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 | 6.1 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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