CVE-2026-64534: Linux kernel · nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path
Source GCVE Database
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| 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
- nvd.nist.gov/vuln/detail/CVE-2026-64534 (opens in a new tab)
- git.kernel.org/stable/c/22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf (opens in a new tab)
- git.kernel.org/stable/c/2ed3c9d955e8cd6361f130623baa664a75fb345f (opens in a new tab)
- git.kernel.org/stable/c/4606467a75cfc16721937272ed29462a750b60c8 (opens in a new tab)
- git.kernel.org/stable/c/ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e (opens in a new tab)
- git.kernel.org/stable/c/c7874dad84b20433c0fe3919f291a762d40de08b (opens in a new tab)
- git.kernel.org/stable/c/d306da8833e75f669d93424fd84940236f3850bc (opens in a new tab)
- git.kernel.org/stable/c/e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1 (opens in a new tab)