CVE-2025-21988Network attack vector

Kernel crash via overwritten donation accounting

Published Apr 2, 2025 · Updated Aug 5, 2026

Race condition in Linux kernel 6.12 through 6.12.19 and 6.13 through 6.13.7 allows remote attackers to crash the kernel. In fs/netfs/read_collect, multiple completed subrequests donating to the same next request replace rather than accumulate next->prev_donated, corrupting donation bookkeeping. A malicious or compromised file server, or an on-path attacker against an unprotected mount, can control reply ordering and short-read boundaries, resulting in data corruption and a kernel BUG crash.

CVSS severity9.8
Critical
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux kernel 6.12 through 6.12.19 and 6.13 through 6.13.7 allows remote attackers to crash the kernel. In fs/netfs/read_collect, multiple completed subrequests donating to the same next request replace rather than accumulate next->prev_donated, corrupting donation bookkeeping. A malicious or compromised file server, or an on-path attacker against an unprotected mount, can control reply ordering and short-read boundaries, resulting in data corruption and a kernel BUG crash.

The record

CVE
CVE-2025-21988
Published
Apr 2, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 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

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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=6.12
  2. Affected versionversion=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <62b9ad7e52d4777f7e775ee1f0ad2452f6041024
  3. Affected versionversion=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <e25cec3b76aba47a49138d2162fc809c6cd49c9e
  4. Affected versionversion=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <e2d46f2ec332533816417b60933954173f602121

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <62b9ad7e52d4777f7e775ee1f0ad2452f6041024; version=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <e25cec3b76aba47a49138d2162fc809c6cd49c9e; version=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <e2d46f2ec332533816417b60933954173f602121

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
9.8LinuxCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application 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

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Your stack

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