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VulnerabilityPublished Updated

CVE-2026-64534: Linux kernel · nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1 : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1, d306da8833e75f669d93424fd84940236f3850bc, c7874dad84b20433c0fe3919f291a762d40de08b +6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=5.10.20 <5.10.261
  • >=5.11.3 <5.12
Fixed in
  • e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1
  • d306da8833e75f669d93424fd84940236f3850bc
  • c7874dad84b20433c0fe3919f291a762d40de08b
  • ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e
  • 4606467a75cfc16721937272ed29462a750b60c8
  • 22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf
  • 5.12
  • 5.10.261
  • 2ed3c9d955e8cd6361f130623baa664a75fb345f
LinuxLinuxAffected
  • =5.12
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected, nvmet_req_uninit() is called unconditionally. However, if the command arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init() had returned false and percpu_ref_tryget_live() was never executed. The unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a refcount underflow, leading to a WARNING in percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and eventually a permanent workqueue deadlock. Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling nvmet_req_uninit(), matching the existing pattern in nvmet_tcp_execute_request().

References

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