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Review reviewCritical

CVE-2026-64535

Linux

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 subseque...

CVSS
9.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.27
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 9.8

Vulnerability overview

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 subseque...

Affected product and versions

Product
Linux
Affected versions
>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 96fe2513df590e74b04253a45089cae75569570e, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e091ff83d962f9ed00d9bd70443676de9fe98bdc, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6f9442983a3e4227afd1c83a5251ddbca585ea21, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 088ee46c18d99baef453afd74181dd40ade044ad, >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < dbbd07d0a7020b80f6a7028e561908f7b83b3d5a, < 6.1.178, < 6.6.145, < 6.12.97, < 6.18.40
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Not available
CVE-2026-64535 — Linux | SECUFOCUS NOW