{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64535","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T15:36:31.795Z","datePublished":"2026-07-27T06:32:34.859Z","dateUpdated":"2026-08-19T16:28:23.449Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-19T16:28:23.449Z"},"descriptions":[{"lang":"en","value":"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\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."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable NVMe/TCP target receive worker processes attacker-controlled H2C_DATA PDUs received through a listening TCP socket, making it remotely network reachable.\nAC:L - The attacker controls digest negotiation, PDU chunking, transfer length, and digest contents, allowing a non-final digest mismatch to be triggered deterministically while keeping other I/O outstanding.\nPR:N - A reasonable non-TLS target deployment using allow_any_host requires no credentials or local capabilities; the remote peer can negotiate data digests and submit the malicious protocol sequence directly.\nUI:N - Exploitation requires only network protocol traffic and no action by a victim user.\nS:U - The vulnerable receive processing and resulting kernel compromise occur within the target host's existing kernel security authority.\nC:H - The premature reference release can free queue, request, response-buffer, and percpu-ref state while asynchronous completions still access it, creating a kernel UAF capable of arbitrary memory disclosure.\nI:H - The kernel UAF exposes writes through reclaimed request and queue structures and is plausibly exploitable for arbitrary kernel memory modification or code execution.\nA:H - The refcount corruption can cause a permanent workqueue teardown deadlock, while the resulting UAF can also produce an oops or kernel panic; the network trigger can be repeated."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/nvme/target/tcp.c"],"versions":[{"version":"91edfca6f8b364d60cde3ddefaf7d03ddf35774b","lessThan":"dfb902462bca478f050224ec7a7195aafa7643b1","status":"affected","versionType":"git"},{"version":"fda871c0ba5d2eed2cd1c881573168129da70058","lessThan":"7e558308eba14c8136cb1e615f0c850f76d1fc0a","status":"affected","versionType":"git"},{"version":"fda871c0ba5d2eed2cd1c881573168129da70058","lessThan":"96fe2513df590e74b04253a45089cae75569570e","status":"affected","versionType":"git"},{"version":"fda871c0ba5d2eed2cd1c881573168129da70058","lessThan":"e091ff83d962f9ed00d9bd70443676de9fe98bdc","status":"affected","versionType":"git"},{"version":"fda871c0ba5d2eed2cd1c881573168129da70058","lessThan":"6f9442983a3e4227afd1c83a5251ddbca585ea21","status":"affected","versionType":"git"},{"version":"fda871c0ba5d2eed2cd1c881573168129da70058","lessThan":"088ee46c18d99baef453afd74181dd40ade044ad","status":"affected","versionType":"git"},{"version":"fda871c0ba5d2eed2cd1c881573168129da70058","lessThan":"dbbd07d0a7020b80f6a7028e561908f7b83b3d5a","status":"affected","versionType":"git"},{"version":"4b17476d809273617d3317fa0d4ae78aa488d760","status":"affected","versionType":"git"},{"version":"5.10.20","lessThan":"5.10.265","status":"affected","versionType":"semver"},{"version":"5.11.3","lessThan":"5.12","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/nvme/target/tcp.c"],"versions":[{"version":"5.12","status":"affected"},{"version":"0","lessThan":"5.12","status":"unaffected","versionType":"semver"},{"version":"5.10.265","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.216","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.178","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.97","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.40","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.20","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"7.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11.3"}]}]}],"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"}],"title":"nvmet-tcp: Fix potential UAF when ddgst mismatch","x_generator":{"engine":"bippy-1.2.0"}}}}