{"id":"CVE-2026-89969","published":"2026-09-16T11:17:07.527","lastModified":"2026-09-16T15:18:21.240","description":"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.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/14cc5a7e77731497d5bea70f3bb05df7eda982e4","tags":[]},{"url":"https://git.kernel.org/stable/c/3a385e0c39efbe34db8edd95900c123113ae3450","tags":[]},{"url":"https://git.kernel.org/stable/c/4f84d42c53c49557fb1ef285c683b0a81b576c74","tags":[]},{"url":"https://git.kernel.org/stable/c/58dc6035b79c4c73c0cbf9ec9f68a7f117b2b3e6","tags":[]},{"url":"https://git.kernel.org/stable/c/a3f0bcfbaf3312a5754d1ce020a07d394669eb25","tags":[]},{"url":"https://git.kernel.org/stable/c/cf5f39d2b58f97e0cd1829c4a6aeef17f1607cca","tags":[]},{"url":"https://git.kernel.org/stable/c/d95d342bc0ea82dc79e6362b2f1f997431750e4c","tags":[]},{"url":"https://git.kernel.org/stable/c/dbc4acbdb3ca8c81441368ad7409b8f77d4de8f6","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"This vulnerability allows an attacker to perform an out-of-bounds write by sending a specially crafted PDU that exceeds the buffer size, potentially leading to kernel memory corruption.","exploitability":"Exploitation requires sending a maliciously crafted PDU over TCP to the affected system. No authentication is needed.","blast_radius":"If exploited, this could lead to arbitrary code execution or denial of service conditions on the target system.","remediation":"Update the Linux kernel to a version that addresses this vulnerability.","tags":["kernel","memory-corruption","remote-exploit"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-23T08:44:18.883Z"}}