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VulnerabilityPublished Updated

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

Source GCVE Database

0
Authoritative record:CVE-2026-64534· Critical 9.8

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

Data as of 26 Oct 2026, 13:47 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.
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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