CVE-2025-21709

Kernel compromise via incomplete mm_struct race

Published Feb 27, 2025 · Updated Aug 5, 2026

Memory corruption in the Linux kernel allows local users to compromise the kernel via a race after dup_mmap() fails during process creation. The failure path drops all locks while its incomplete mm_struct remains reachable through reverse mappings, letting memory-management iterators follow invalid or stale VMA pointers. An unprivileged local process can induce the failed fork through memory pressure or interruption; the resulting use-after-free can expose or corrupt memory and crash or hang the system.

CVSS severity7.8
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Memory corruption in the Linux kernel allows local users to compromise the kernel via a race after dup_mmap() fails during process creation. The failure path drops all locks while its incomplete mm_struct remains reachable through reverse mappings, letting memory-management iterators follow invalid or stale VMA pointers. An unprivileged local process can induce the failed fork through memory pressure or interruption; the resulting use-after-free can expose or corrupt memory and crash or hang the system.

The record

CVE
CVE-2025-21709
Published
Feb 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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=6.8
  2. Affected versionversion=d2406291483775ecddaee929231a39c70c08fda2 <64c37e134b120fb462fb4a80694bfb8e7be77b14
  3. Affected versionversion=d2406291483775ecddaee929231a39c70c08fda2 <74c2471eb891a7dcb3874b21c106cda75f52be30
  4. Affected versionversion=d2406291483775ecddaee929231a39c70c08fda2 <da139948aeda677ac09cc0e7d837f8a314de7d55

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.8; version=d2406291483775ecddaee929231a39c70c08fda2 <64c37e134b120fb462fb4a80694bfb8e7be77b14; version=d2406291483775ecddaee929231a39c70c08fda2 <74c2471eb891a7dcb3874b21c106cda75f52be30; version=d2406291483775ecddaee929231a39c70c08fda2 <da139948aeda677ac09cc0e7d837f8a314de7d55

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1OracleCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo