PT-2025-8863 · Linux+1 · Linux Kernel+1

Published 2025-01-02 · Updated 2026-05-26 · CVE-2025-21751

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A use-after-free issue occurs in the Linux kernel when a firmware failure happens during the matcher disconnect flow in the net/mlx5 module. This leads to a freed matcher on the matchers list, causing a crash. The problem arises from the error flow of the function reconnecting the matcher back and returning an error, allowing the calling function to continue running and eventually free the matcher being disconnected. This issue can result in bad steering state and resource leakage.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Double Free

Use After Free

Weakness Enumeration

CWE-415

CWE-416

Related Identifiers

BDU:2025-03900

CVE-2025-21751

DSA-6008-1

ECHO-F70E-B3F2-3BEE

Affected Products

Debian

Linux Kernel

References · 26

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21751.json · Exploit
• https://git.kernel.org/stable/c/23a86c76a1a197e8fbbbd0ce3e826eb58c471624 · Patch
• https://osv.dev/vulnerability/DSA-6008-1 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-DEBIAN-13-CVE-2025-21751 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2025-21751 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21751 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2025-21751 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-21751 · Security Note
• https://osv.dev/vulnerability/ROOT-OS-DEBIAN-12-CVE-2025-21751 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-UBUNTU-2404-CVE-2025-21751 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-DEBIAN-11-CVE-2025-21751 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2025-21751 · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-03900 · Security Note
• https://wiki.astralinux.ru/astra-linux-se18-bulletin-2026-0224SE18 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-UBUNTU-2204-CVE-2025-21751 · Vendor Advisory