GHSA-PCVM-4G32-RVG7
Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31In the Linux kernel, the following vulnerability has been resolved:
nvmet-tcp: fix out-of-bounds write when receiving an over-long PDU
nvmet_tcp_try_recv_pdu() reads a PDU header into the fixed 128-byte queue->pdu union, then computes the remaining payload length as
queue->left = hdr->hlen - queue->offset + hdgst;
and reads that many more bytes into &queue->pdu + queue->offset, without ever bounding the result against sizeof(queue->pdu).
A struct nvme_tcp_icreq_pdu is itself 128 bytes, exactly the size of the union. Once a header digest has been negotiated (hdgst = 4), a second ICReq passes the hlen == nvmet_tcp_pdu_size() check but yields queue->left = 128 - 8 + 4 = 124, so bytes 8..132 are written into the 128-byte buffer -- 4 bytes past its end, over queue->hdr_digest and queue->data_digest. Those bytes are attacker-controlled (an ICReq carries no digest), and the duplicate ICReq is only rejected later, after the overflow. A remote unauthenticated host can thus corrupt kernel memory adjacent to the receive buffer.
Reject any PDU whose declared length would read past the end of queue->pdu before the second recv.
{
"affected": [],
"aliases": [
"CVE-2026-89969"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T11:17:07Z",
"severity": "CRITICAL"
},
"details": "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-\u003epdu union, then computes the remaining payload length as\n\n\tqueue-\u003eleft = hdr-\u003ehlen - queue-\u003eoffset + hdgst;\n\nand reads that many more bytes into \u0026queue-\u003epdu + queue-\u003eoffset, without\never bounding the result against sizeof(queue-\u003epdu).\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-\u003eleft = 128 - 8 + 4 = 124, so bytes 8..132 are written into the\n128-byte buffer -- 4 bytes past its end, over queue-\u003ehdr_digest and\nqueue-\u003edata_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-\u003epdu before the second recv.",
"id": "GHSA-pcvm-4g32-rvg7",
"modified": "2026-09-16T15:31:03Z",
"published": "2026-09-16T12:30:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89969"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/14cc5a7e77731497d5bea70f3bb05df7eda982e4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3a385e0c39efbe34db8edd95900c123113ae3450"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4f84d42c53c49557fb1ef285c683b0a81b576c74"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/58dc6035b79c4c73c0cbf9ec9f68a7f117b2b3e6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a3f0bcfbaf3312a5754d1ce020a07d394669eb25"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cf5f39d2b58f97e0cd1829c4a6aeef17f1607cca"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d95d342bc0ea82dc79e6362b2f1f997431750e4c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dbc4acbdb3ca8c81441368ad7409b8f77d4de8f6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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