CVE-2025-40343Network attack vector

Unauthenticated kernel compromise via repeated association deletion

Published Dec 9, 2025 · Updated Aug 5, 2026

Use-after-free in Linux nvmet-fc allows remote attackers to corrupt kernel memory through repeated FC-NVMe association teardown. The deletion path queues the same association work twice because it checks the terminating state only after scheduling, so the second run accesses and frees reclaimed objects. An unauthenticated host port with FC/FCoE fabric access can trigger kernel-data disclosure, control-flow hijack, or a kernel panic.

CVSS severity9.8
Critical
EPSS probability0.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux nvmet-fc allows remote attackers to corrupt kernel memory through repeated FC-NVMe association teardown. The deletion path queues the same association work twice because it checks the terminating state only after scheduling, so the second run accesses and frees reclaimed objects. An unauthenticated host port with FC/FCoE fabric access can trigger kernel-data disclosure, control-flow hijack, or a kernel panic.

The record

CVE
CVE-2025-40343
Published
Dec 9, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 9, 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=4.8
  2. Affected versionversion=a07b4970f464f13640e28e16dad6cfa33647cc99 <04d17540ef51e2c291eb863ca87fd332259b2d40
  3. Affected versionversion=a07b4970f464f13640e28e16dad6cfa33647cc99 <2f4852db87e25d4e226b25cb6f652fef9504360e
  4. Affected versionversion=a07b4970f464f13640e28e16dad6cfa33647cc99 <601ed47b2363c24d948d7bac0c23abc8bd459570
  5. Affected versionversion=a07b4970f464f13640e28e16dad6cfa33647cc99 <85e2ce1920cb511d57aae59f0df6ff85b28bf04d
  6. Affected versionversion=a07b4970f464f13640e28e16dad6cfa33647cc99 <c09ac9a63fc3aaf4670ad7b5e4f5afd764424154
  7. Affected versionversion=a07b4970f464f13640e28e16dad6cfa33647cc99 <f2537be4f8421f6495edfa0bc284d722f253841d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.8; version=a07b4970f464f13640e28e16dad6cfa33647cc99 <04d17540ef51e2c291eb863ca87fd332259b2d40; version=a07b4970f464f13640e28e16dad6cfa33647cc99 <2f4852db87e25d4e226b25cb6f652fef9504360e; version=a07b4970f464f13640e28e16dad6cfa33647cc99 <601ed47b2363c24d948d7bac0c23abc8bd459570; version=a07b4970f464f13640e28e16dad6cfa33647cc99 <85e2ce1920cb511d57aae59f0df6ff85b28bf04d; version=a07b4970f464f13640e28e16dad6cfa33647cc99 <c09ac9a63fc3aaf4670ad7b5e4f5afd764424154; version=a07b4970f464f13640e28e16dad6cfa33647cc99 <f2537be4f8421f6495edfa0bc284d722f253841d

Published CVSS scores

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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1210Exploitation of Remote Services

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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