CVE-2025-21927

Kernel memory corruption via unchecked header length

Published Apr 1, 2025 · Updated Aug 5, 2026

Memory corruption in the Linux kernel nvme-tcp client allows local users to corrupt kernel memory through a malicious NVMe/TCP target. The nvme_tcp_recv_pdu() path accepts an invalid header length, and nvme_tcp_verify_hdgst() writes the calculated digest beyond the allocated header area. Exploitation requires an NVMe/TCP connection with header digests enabled; the published consequence is kernel-memory corruption, not demonstrated code execution.

CVSS severity7.8
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in the Linux kernel nvme-tcp client allows local users to corrupt kernel memory through a malicious NVMe/TCP target. The nvme_tcp_recv_pdu() path accepts an invalid header length, and nvme_tcp_verify_hdgst() writes the calculated digest beyond the allocated header area. Exploitation requires an NVMe/TCP connection with header digests enabled; the published consequence is kernel-memory corruption, not demonstrated code execution.

The record

CVE
CVE-2025-21927
Published
Apr 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 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

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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=3f2304f8c6d6ed97849057bd16fee99e434ca796 <22b06c89aa6b2d1ecb8aea72edfb9d53af8d5126
  2. Affected versionversion=3f2304f8c6d6ed97849057bd16fee99e434ca796 <9fbc953d6b38bc824392e01850f0aeee3b348722
  3. Affected versionversion=3f2304f8c6d6ed97849057bd16fee99e434ca796 <ad95bab0cd28ed77c2c0d0b6e76e03e031391064
  4. Affected versionversion=5.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3f2304f8c6d6ed97849057bd16fee99e434ca796 <22b06c89aa6b2d1ecb8aea72edfb9d53af8d5126; version=3f2304f8c6d6ed97849057bd16fee99e434ca796 <9fbc953d6b38bc824392e01850f0aeee3b348722; version=3f2304f8c6d6ed97849057bd16fee99e434ca796 <ad95bab0cd28ed77c2c0d0b6e76e03e031391064; version=5.0

Published CVSS scores

7.8NIST NVDCVSS: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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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