Detections
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Echo: xorg-server: security update to 2:21.1.16-1.3+deb13u2+e2

high Tenable Self-Hosted Container Security Plugin ID 455211

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - A use-after-free flaw was found in the X.Org X server and Xwayland in miSyncDestroyFence(). A client that
 sets up multiple fence triggers can trigger a use-after-free function pointer call. An attacker would
 connect to the X server to set up a fence and await that fence, then a second X connection destroys the
 fence, causing the use-after-free. This may be used to crash the server, or for privilege escalation if
 the X server runs as root. (CVE-2026-50257)

Solution

Update the xorg-server library and its related packages to version 2:21.1.16-1.3+deb13u2+e2 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-50257

Plugin Details

Severity: High

ID: 455211

Version: Revision 1.1

Type: Local

Published: 10/1/2026

Updated: 10/1/2026

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.98

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-50257

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 6/5/2026

Vulnerability Publication Date: 6/1/2026

Reference Information

CVE: CVE-2026-50257