CVE-2025-39924Public exploit

Kernel crash via unchecked EROFS algorithm index

Published Oct 1, 2025 · Updated Aug 5, 2026

Out-of-bounds access in EROFS in Linux 6.15 through 6.16.7 allows attackers to crash the kernel via a crafted filesystem image. The encoded-extent parser derives a 4-bit algorithm index from ext->plen and uses values 7 through 15 beyond the six-entry z_erofs_decomp table. Triggering requires the image to be mounted and a file read; the invalid entry is dereferenced and invoked as a decompressor, causing an oops or kernel crash.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 17, 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

Out-of-bounds access in EROFS in Linux 6.15 through 6.16.7 allows attackers to crash the kernel via a crafted filesystem image. The encoded-extent parser derives a 4-bit algorithm index from ext->plen and uses values 7 through 15 beyond the six-entry z_erofs_decomp table. Triggering requires the image to be mounted and a file read; the invalid entry is dereferenced and invoked as a decompressor, causing an oops or kernel crash.

The record

CVE
CVE-2025-39924
Published
Oct 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 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=1d191b4ca51d73699cb127386b95ac152af2b930 <131897c65e2b86cf14bec7379f44aa8fbb407526
  2. Affected versionversion=1d191b4ca51d73699cb127386b95ac152af2b930 <db5d7abd379a8dcf030be8f52f99cadf7e397ba8
  3. Affected versionversion=6.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1d191b4ca51d73699cb127386b95ac152af2b930 <131897c65e2b86cf14bec7379f44aa8fbb407526; version=1d191b4ca51d73699cb127386b95ac152af2b930 <db5d7abd379a8dcf030be8f52f99cadf7e397ba8; version=6.15

Published CVSS scores

5.5CISACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.

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

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1204.002Malicious File

Public exploit references

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