GHSA-9677-C9P4-RGM3
Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30In the Linux kernel, the following vulnerability has been resolved:
net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length
ncsi_send_cmd_nl() takes the number of bytes to copy from the attacker-controlled ncsi_pkt_hdr.length field of the in-band packet header, while the source buffer is the NCSI_ATTR_DATA netlink attribute whose readable size is nla_len() - sizeof(ncsi_pkt_hdr). The two length sources are never cross-checked: only nla_len() >= sizeof(struct ncsi_pkt_hdr) is enforced.
With hdr->length set larger than the attribute payload (up to 65535 against at most 2032 readable bytes), ncsi_cmd_handler_oem() copies past the end of the netlink attribute buffer with unsafe_memcpy(), leaking up to ~64KB of kernel heap memory into the transmitted NCSI command packet. The destination skb is sized by the declared payload, so the write side does not overflow - this is a pure OOB read / information leak, reachable with CAP_NET_ADMIN on systems with a registered NCSI device (e.g. OpenBMC on Aspeed BMC SoCs, where NET_NCSI=y is standard).
Reject commands whose declared payload extends past the end of the data attribute.
The issue was found by the autokbug dynamic kernel fuzzer at Tencent Yunding Lab.
{
"affected": [],
"aliases": [
"CVE-2026-74694"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-22T16:16:43Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length\n\nncsi_send_cmd_nl() takes the number of bytes to copy from the\nattacker-controlled ncsi_pkt_hdr.length field of the in-band packet\nheader, while the source buffer is the NCSI_ATTR_DATA netlink\nattribute whose readable size is nla_len() - sizeof(ncsi_pkt_hdr).\nThe two length sources are never cross-checked: only\nnla_len() \u003e= sizeof(struct ncsi_pkt_hdr) is enforced.\n\nWith hdr-\u003elength set larger than the attribute payload (up to 65535\nagainst at most 2032 readable bytes), ncsi_cmd_handler_oem() copies\npast the end of the netlink attribute buffer with unsafe_memcpy(),\nleaking up to ~64KB of kernel heap memory into the transmitted NCSI\ncommand packet. The destination skb is sized by the declared payload,\nso the write side does not overflow - this is a pure OOB read /\ninformation leak, reachable with CAP_NET_ADMIN on systems with a\nregistered NCSI device (e.g. OpenBMC on Aspeed BMC SoCs, where\nNET_NCSI=y is standard).\n\nReject commands whose declared payload extends past the end of the\ndata attribute.\n\nThe issue was found by the autokbug dynamic kernel fuzzer at Tencent\nYunding Lab.",
"id": "GHSA-9677-c9p4-rgm3",
"modified": "2026-08-22T18:30:29Z",
"published": "2026-08-22T18:30:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74694"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/02226af69362758046822840fc6a497f5de33f00"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3a60b5af75abe8e3494ccd074fb4ae6e601a3e55"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/43c7d0a6917751ea898ae584d00f24f5deac46d4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4489b4a17892750131e4bef4bc1d3d703c8fb5ba"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/67c72b8ef63d9d9a610546fda30b116638f39745"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/afa58b7384913c8773d837acdb07b035690ec5d2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b5231ad0b376b801ab8cf2962b182cc29deaedb3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e60afa01d35f8b2671b27ca93309921427144cce"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.