CVE-2025-21893Public exploit

Local kernel memory corruption via key_put race

Published Mar 31, 2025 · Updated Aug 5, 2026

Use-after-free in Linux kernel 6.10 through 6.13.8 allows local users to read or corrupt kernel memory through keyring syscalls. After key_put() drops the last reference and updates quota data, garbage collection reads the freed key's usage count instead of a final-put flag. Unprivileged key churn can win the repeatable race, causing kernel memory disclosure, corruption, or a panic without user interaction.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel 6.10 through 6.13.8 allows local users to read or corrupt kernel memory through keyring syscalls. After key_put() drops the last reference and updates quota data, garbage collection reads the freed key's usage count instead of a final-put flag. Unprivileged key churn can win the repeatable race, causing kernel memory disclosure, corruption, or a panic without user interaction.

The record

CVE
CVE-2025-21893
Published
Mar 31, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 31, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.10
  2. Affected versionversion=9578e327b2b4935a25d49e3891b8fcca9b6c10c6 <6afe2ea2daec156bd94ad2c5a6f4f4c48240dcd3
  3. Affected versionversion=9578e327b2b4935a25d49e3891b8fcca9b6c10c6 <75845c6c1a64483e9985302793dbf0dfa5f71e32
  4. Affected versionversion=9578e327b2b4935a25d49e3891b8fcca9b6c10c6 <f6a3cf833188e897c97028cd7b926e3f2cb1a8c0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.10; version=9578e327b2b4935a25d49e3891b8fcca9b6c10c6 <6afe2ea2daec156bd94ad2c5a6f4f4c48240dcd3; version=9578e327b2b4935a25d49e3891b8fcca9b6c10c6 <75845c6c1a64483e9985302793dbf0dfa5f71e32; version=9578e327b2b4935a25d49e3891b8fcca9b6c10c6 <f6a3cf833188e897c97028cd7b926e3f2cb1a8c0

Published CVSS scores

7.1Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.8Linux CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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