{"id":"CVE-2026-64535","title":"nvmet-tcp: Fix potential UAF when ddgst mismatch","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: Fix potential UAF when ddgst mismatch\n\nShivam Kumar found via vulnerability testing:\nWhen data digest is enabled on an NVMe/TCP connection and a digest\nmisma…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 91edfca6f8b364d60cde3ddefaf7d03ddf35774b < dfb902462bca478f050224ec7a7195aafa7643b1","Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 7e558308eba14c8136cb1e615f0c850f76d1fc0a","Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 96fe2513df590e74b04253a45089cae75569570e","Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < e091ff83d962f9ed00d9bd70443676de9fe98bdc","Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 6f9442983a3e4227afd1c83a5251ddbca585ea21","Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 088ee46c18d99baef453afd74181dd40ade044ad","Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < dbbd07d0a7020b80f6a7028e561908f7b83b3d5a","Linux 4b17476d809273617d3317fa0d4ae78aa488d760","Linux >= 5.10.20 < 5.10.265","Linux >= 5.11.3 < 5.12","Linux 5.12"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T15:41:56.047833Z"},"published":"2026-07-27","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:42:40.573Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64535","references":[{"url":"https://git.kernel.org/stable/c/dfb902462bca478f050224ec7a7195aafa7643b1"},{"url":"https://git.kernel.org/stable/c/7e558308eba14c8136cb1e615f0c850f76d1fc0a"},{"url":"https://git.kernel.org/stable/c/96fe2513df590e74b04253a45089cae75569570e"},{"url":"https://git.kernel.org/stable/c/e091ff83d962f9ed00d9bd70443676de9fe98bdc"},{"url":"https://git.kernel.org/stable/c/6f9442983a3e4227afd1c83a5251ddbca585ea21"},{"url":"https://git.kernel.org/stable/c/088ee46c18d99baef453afd74181dd40ade044ad"},{"url":"https://git.kernel.org/stable/c/dbbd07d0a7020b80f6a7028e561908f7b83b3d5a"}],"tags":["cve.org"],"epss":0.00547,"epssPercentile":0.44668,"ingestedAt":"2026-10-16T17:24:46.827Z","slug":"CVE-2026-64535","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: Fix potential UAF when ddgst mismatch\n\nShivam Kumar found via vulnerability testing:\nWhen data digest is enabled on an NVMe/TCP connection and a digest\nmismatch occurs on a non-final H2C_DATA PDU during an R2T-based\ndata transfer, the digest error handler in nvmet_tcp_try_recv_ddgst()\ncalls nvmet_req_uninit() — which performs percpu_ref_put() on the\nsubmission queue — but does NOT mark the command as completed. It\ndoes not set cqe->status, does not modify rbytes_done, and does not\nclear any flag. When the subsequent fatal error triggers queue\nteardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands,\nchecks nvmet_tcp_need_data_in() for each one, and finds that the\nalready-uninited command still appears to need data (because\nrbytes_done < transfer_len and cqe->status == 0). It therefore calls\nnvmet_req_uninit() a second time on the same command — a double\npercpu_ref_put against a single percpu_ref_get.\n\n## Affected\n\n- `Linux >= 91edfca6f8b364d60cde3ddefaf7d03ddf35774b < dfb902462bca478f050224ec7a7195aafa7643b1`\n- `Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 7e558308eba14c8136cb1e615f0c850f76d1fc0a`\n- `Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 96fe2513df590e74b04253a45089cae75569570e`\n- `Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < e091ff83d962f9ed00d9bd70443676de9fe98bdc`\n- `Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 6f9442983a3e4227afd1c83a5251ddbca585ea21`\n- `Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < 088ee46c18d99baef453afd74181dd40ade044ad`\n- `Linux >= fda871c0ba5d2eed2cd1c881573168129da70058 < dbbd07d0a7020b80f6a7028e561908f7b83b3d5a`\n- `Linux 4b17476d809273617d3317fa0d4ae78aa488d760`\n- `Linux >= 5.10.20 < 5.10.265`\n- `Linux >= 5.11.3 < 5.12`\n- `Linux 5.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}