Vulnary
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Critical· 9.8official fix available

CVE-2025-21954

A critical vulnerability in the Linux kernel's netmem subsystem could allow transmission of unreadable socket buffers, potentially causing unsafe DMA mapping operations. The flaw has been resolved by preventing the transmission of such unreadable skbs. Users should apply the kernel update that addresses this issue to mitigate the risk.

publishedApr 1, 2025
last modifiedJul 30, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
37th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 29, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Linux kernel users

02

Real-world impact

Could lead to improper DMA mapping and possible system instability or privilege escalation.

03

Why this severity

CVSS 9.8 (Critical) due to network attack vector, low complexity, no privileges or user interaction required, with high impact on confidentiality, integrity, and availability.

04

What to do about it

official fix available
recommended steps
  1. 01Obtain and install the Linux kernel update that includes the fix for CVE-2025-21954.
  2. 02Reboot the system to load the patched kernel.

NVD-referenced vendor advisory

05

Timeline

  1. Apr 1, 2025 · Apr 1, 2025
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 30, 2026 · 7d ago
    Advisory updated
    The NVD record was last revised.
  3. Jul 30, 2026 · 6d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
CVE-2025-21954: A critical vulnerability in the Linux kernel's netmem subsystem could · Vulnary