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VulnerabilityPublished Updated

CVE-2025-21872: Linux kernel · efi: Don't map the entire mokvar table to determine its size

Affects Linux kernelSource GCVE Database

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Not known to be exploited.

Data as of 30 Oct 2026, 14:18 UTC

Severity
Medium

Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by modifying the efi_mokvar_table_init() function. Users should apply the updated kernel version containing this fix. No additional mitigation steps are required beyond applying the official patch.

Description

A vulnerability in the Linux kernel's EFI mokvar table handling was fixed by changing how the table is mapped during initialization. Previously, the entire mokvar table was mapped repeatedly to determine its size, which could fail and cause kernel warnings and tracebacks when the table was large. The fix involves mapping only each entry header individually and enforcing NUL termination of variable names, avoiding the need to map the entire table.

References

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