nvmet-tcp: Fix potential UAF when ddgst mismatch
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 6 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-415 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() — which performs percpu_ref_put() on the submission queue — but does NOT mark the command as completed. It does not set cqe->status, does not modify rbytes_done, and does not clear any flag. When the subsequent fatal error triggers queue teardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands, checks nvmet_tcp_need_data_in() for each one, and finds that the already-uninited command still appears to need data (because rbytes_done < transfer_len and cqe->status == 0). It therefore calls nvmet_req_uninit() a second time on the same command — a double percpu_ref_put against a single percpu_ref_get.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.12
- Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.15.216, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux for NVIDIA 26 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-64535
- 2026-10-03 Alias added: GHSA-5wfv-mpg7-6vcr
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-20 Weakness changed · CISA ADP
- 2026-11-06 Affected versions changed · Red Hat
References
Other 7
- https://git.kernel.org/stable/c/dfb902462bca478f050224ec7a7195aafa7643b1
- https://git.kernel.org/stable/c/7e558308eba14c8136cb1e615f0c850f76d1fc0a
- https://git.kernel.org/stable/c/96fe2513df590e74b04253a45089cae75569570e
- https://git.kernel.org/stable/c/e091ff83d962f9ed00d9bd70443676de9fe98bdc
- https://git.kernel.org/stable/c/6f9442983a3e4227afd1c83a5251ddbca585ea21
- https://git.kernel.org/stable/c/088ee46c18d99baef453afd74181dd40ade044ad
- https://git.kernel.org/stable/c/dbbd07d0a7020b80f6a7028e561908f7b83b3d5a
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Sources
- CVE-2026-64535 · CVE Program
- CVE-2026-64535 · NVD
- FIRST EPSS
- GHSA-5wfv-mpg7-6vcr · GitHub Advisory Database · CC BY 4.0
- CVE-2026-64535 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences