CVE-2025-38194

Kernel crash via unchecked JFFS2 preallocation failure

Published Jul 4, 2025 · Updated May 11, 2026

Unchecked return handling in Linux JFFS2 from 2.6.18 allows local users to trigger a kernel crash during filesystem writes. jffs2_sum_write_sumnode ignores a failed jffs2_prealloc_raw_node_refs call and invokes jffs2_sum_write_data, which links a summary to a node that was never allocated. Reachability requires a writable JFFS2 filesystem and a preallocation failure; the published reproduction used fault injection, and the bounded result was a kernel BUG and service interruption.

CVSS severity5.5
Medium
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

Unchecked return handling in Linux JFFS2 from 2.6.18 allows local users to trigger a kernel crash during filesystem writes. jffs2_sum_write_sumnode ignores a failed jffs2_prealloc_raw_node_refs call and invokes jffs2_sum_write_data, which links a summary to a node that was never allocated. Reachability requires a writable JFFS2 filesystem and a preallocation failure; the published reproduction used fault injection, and the bounded result was a kernel BUG and service interruption.

The record

CVE
CVE-2025-38194
Published
Jul 4, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-252, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 4, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=2.6.18
  2. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <337f80f3d546e131c7aa90b61d8cde051ae858c7
  3. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <346cfb9d19ea7feb6fb57917b21c4797fb444dab
  4. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <3f46644a5131a4793fc95c32a7d0a769745b06e7
  5. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <4adee34098a6ee86a54bf3ec885eab620c126a6b
  6. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <8ce46dc5b10b0b6f67663202a4921b0e11ad7367
  7. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <c0edcdb4fc106d69a2d1a0ce4868193511c389f3
  8. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <da12ef7e19048dc5714032c2db587a215852b200
  9. Affected versionversion=2f785402f39b96a077b6e62bf26164bfb8e0c980 <ec9e6f22bce433b260ea226de127ec68042849b0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.18; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <337f80f3d546e131c7aa90b61d8cde051ae858c7; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <346cfb9d19ea7feb6fb57917b21c4797fb444dab; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <3f46644a5131a4793fc95c32a7d0a769745b06e7; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <4adee34098a6ee86a54bf3ec885eab620c126a6b; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <8ce46dc5b10b0b6f67663202a4921b0e11ad7367; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <c0edcdb4fc106d69a2d1a0ce4868193511c389f3; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <da12ef7e19048dc5714032c2db587a215852b200; version=2f785402f39b96a077b6e62bf26164bfb8e0c980 <ec9e6f22bce433b260ea226de127ec68042849b0

Published CVSS scores

7.0Oracle LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-252Unchecked Return Value
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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