{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89969","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.778Z","datePublished":"2026-09-16T10:32:49.603Z","dateUpdated":"2026-09-16T14:40:48.122Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-16T14:40:48.122Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet-tcp: fix out-of-bounds write when receiving an over-long PDU\n\nnvmet_tcp_try_recv_pdu() reads a PDU header into the fixed 128-byte\nqueue->pdu union, then computes the remaining payload length as\n\n\tqueue->left = hdr->hlen - queue->offset + hdgst;\n\nand reads that many more bytes into &queue->pdu + queue->offset, without\never bounding the result against sizeof(queue->pdu).\n\nA struct nvme_tcp_icreq_pdu is itself 128 bytes, exactly the size of the\nunion. Once a header digest has been negotiated (hdgst = 4), a second\nICReq passes the hlen == nvmet_tcp_pdu_size() check but yields\nqueue->left = 128 - 8 + 4 = 124, so bytes 8..132 are written into the\n128-byte buffer -- 4 bytes past its end, over queue->hdr_digest and\nqueue->data_digest. Those bytes are attacker-controlled (an ICReq\ncarries no digest), and the duplicate ICReq is only rejected later,\nafter the overflow. A remote unauthenticated host can thus corrupt\nkernel memory adjacent to the receive buffer.\n\nReject any PDU whose declared length would read past the end of\nqueue->pdu before the second recv."}],"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 flaw is in nvmet-tcp, an in-kernel NVMe-over-TCP target that accepts remote TCP connections; nvmet_tcp_try_recv_pdu() copies attacker-controlled PDU bytes from the socket, so the overflow is reachable from any network peer that can connect to an exposed NVMe-oF TCP port (typical cloud/storage-server deployment).\nAC:L - The attacker enables header digest in the first ICReq (the target copies the initiator's digest flags with no extra configuration), then sends a second 128-byte ICReq; queue->left becomes 124 and four attacker-controlled bytes are written past queue->pdu with no race or condition outside attacker control.\nPR:N - The overflow fires on a duplicate ICReq after TCP accept and digest negotiation, before NVMe Connect, host NQN allow-list, or DH-HMAC-CHAP in-band authentication; no Linux credentials or capabilities on the target are required.\nUI:N - Exploitation requires only attacker-sent NVMe/TCP PDUs to an already listening target port; no victim user action such as mounting a filesystem or opening a device is needed.\nS:U - The out-of-bounds write corrupts fields of the host's nvmet_tcp_queue in kernel memory and does not cross a VM, hypervisor, container, or IOMMU security boundary.\nC:H - Attacker-controlled 4-byte overflow into kernel memory adjacent to queue->pdu is memory corruption that, per kernel guidance, can be leveraged for information disclosure (including by clearing hdr_digest so later verify_hdgst is skipped and by controlling the persisted digest-flag bytes).\nI:H - This is an attacker-controlled out-of-bounds write past the 128-byte queue->pdu union into adjacent kernel fields (hdr_digest and data_digest); per kernel guidance an OOB write is High integrity impact and can disable PDU digest verification before the duplicate ICReq is rejected.\nA:H - After the overflow, nvmet_tcp_done_recv_pdu() returns -EPROTO and nvmet_tcp_socket_error() calls nvmet_ctrl_fatal_error() once a controller exists (e.g. after unauthenticated Discovery Connect), taking down the NVMe target; the kernel memory corruption can also oops, and the trigger is remotely repeatable."}]}],"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":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"a3f0bcfbaf3312a5754d1ce020a07d394669eb25","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"4f84d42c53c49557fb1ef285c683b0a81b576c74","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"58dc6035b79c4c73c0cbf9ec9f68a7f117b2b3e6","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"cf5f39d2b58f97e0cd1829c4a6aeef17f1607cca","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"3a385e0c39efbe34db8edd95900c123113ae3450","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"dbc4acbdb3ca8c81441368ad7409b8f77d4de8f6","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"d95d342bc0ea82dc79e6362b2f1f997431750e4c","status":"affected","versionType":"git"},{"version":"872d26a391da92ed8f0c0f5cb5fef428067b7f30","lessThan":"14cc5a7e77731497d5bea70f3bb05df7eda982e4","status":"affected","versionType":"git"}]},{"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":"5.0","status":"affected"},{"version":"0","lessThan":"5.0","status":"unaffected","versionType":"semver"},{"version":"5.10.270","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.110","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.51","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.5","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc2","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":"5.0","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.18.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.3-rc2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a3f0bcfbaf3312a5754d1ce020a07d394669eb25"},{"url":"https://git.kernel.org/stable/c/4f84d42c53c49557fb1ef285c683b0a81b576c74"},{"url":"https://git.kernel.org/stable/c/58dc6035b79c4c73c0cbf9ec9f68a7f117b2b3e6"},{"url":"https://git.kernel.org/stable/c/cf5f39d2b58f97e0cd1829c4a6aeef17f1607cca"},{"url":"https://git.kernel.org/stable/c/3a385e0c39efbe34db8edd95900c123113ae3450"},{"url":"https://git.kernel.org/stable/c/dbc4acbdb3ca8c81441368ad7409b8f77d4de8f6"},{"url":"https://git.kernel.org/stable/c/d95d342bc0ea82dc79e6362b2f1f997431750e4c"},{"url":"https://git.kernel.org/stable/c/14cc5a7e77731497d5bea70f3bb05df7eda982e4"}],"title":"nvmet-tcp: fix out-of-bounds write when receiving an over-long PDU","x_generator":{"engine":"bippy-1.2.0"}}}}