CVE-2026-64534
In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: check INIT_FAILED…
- Risk score
- 79/100
- CVSS
- 9.8 v3.1
- Published
- 27 Jul 2026
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What to know
- What it is
- A critical vulnerability in the Linux kernel affects the nvmet-tcp module, allowing an attacker to cause a permanent workqueue deadlock and potentially leading to a use-after-free diagnostic.
- Affected
- {'product': 'Ubuntu Linux', 'vendor': 'Canonical'}
- Fix
- Check the linked advisory for the fix, as no specific version is given.
- Exploitation
- No known exploitation
Story map
At a glance
Canonical Ubuntu Linux: Red, act today. A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format references the map's regex capture variables before referencing the map output variable. An unauthenticated attacker can exploit this vulnerability by sending crafted HTTP requests, causing a heap buffer overflow in the NGINX worker process leading to a restart, or potential…
The flaws
- CVE-2026-64534: In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: check INIT_FAILED… (CVSS 9.8)
- CVE-2026-93479: Heap buffer overflow can lead to remote code execution (CVSS 8.1 · EPSS 1%)
- CVE-2026-15176: Heap buffer overflow can lead to remote code execution (CVSS 8.1 · EPSS 1%)
- CVE-2026-97205: NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module (CVSS 8.1 · EPSS 1%)
The fix
Fix: Check the linked advisory for the concrete fix.
Who is exposed: {'products': ['NGINX Plus', 'NGINX Open Source'], 'packages': [], 'versions': []}
Where it stands
- No known exploitation
How it unfolded
- 26 Oct, Ubuntu security notices (official): USN-8955-1: nginx vulnerabilities
- 5 Nov, Ubuntu security notices (official): USN-8955-2: nginx vulnerabilities
- 6 Nov, Ubuntu security notices (official): USN-9003-1: Linux kernel (NVIDIA) vulnerabilities
Connects to
- Same weakness: CWE-667 (CWE-667). 10 other warnings in 30 days
- Same product: Earlier Canonical Ubuntu Linux warnings. 163 in the last 90 days
Why it is Amber
- CVSS 9.8 critical
- Remotely exploitable without logging in
- On your watchlist: linux kernel
- Named in a government or vendor bulletin
Government and vendor bulletins
References
- https://ubuntu.com/security/notices/USN-9003-1
- https://git.kernel.org/stable/c/22ec7a9fe9153d2737ee9b2fa6d2e43a1491decf
- https://git.kernel.org/stable/c/2ed3c9d955e8cd6361f130623baa664a75fb345f
- https://git.kernel.org/stable/c/4606467a75cfc16721937272ed29462a750b60c8
- https://git.kernel.org/stable/c/ba35b1c674ca3841c0dfadd698f2c1b3ec542d4e
- https://git.kernel.org/stable/c/c7874dad84b20433c0fe3919f291a762d40de08b
- https://git.kernel.org/stable/c/d306da8833e75f669d93424fd84940236f3850bc
- https://git.kernel.org/stable/c/e602c93b25bda4a9d0ff1791a4bdbfdcbb074af1
Original 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().
Last activity 6 Nov 2026. Patch Forecast updates every hour.