CVE-2026-74694 (GCVE-0-2026-74694)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-22 15:32
VLAI
Title
net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length
Summary
In 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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < e60afa01d35f8b2671b27ca93309921427144cce (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < 67c72b8ef63d9d9a610546fda30b116638f39745 (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < 4489b4a17892750131e4bef4bc1d3d703c8fb5ba (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < 43c7d0a6917751ea898ae584d00f24f5deac46d4 (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < b5231ad0b376b801ab8cf2962b182cc29deaedb3 (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < 02226af69362758046822840fc6a497f5de33f00 (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < 3a60b5af75abe8e3494ccd074fb4ae6e601a3e55 (git)
Affected: 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 , < afa58b7384913c8773d837acdb07b035690ec5d2 (git)
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Linux Linux Affected: 4.20
Unaffected: 0 , < 4.20 (semver)
Unaffected: 5.10.265 , ≤ 5.10.* (semver)
Unaffected: 5.15.216 , ≤ 5.15.* (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.152 , ≤ 6.6.* (semver)
Unaffected: 6.12.104 , ≤ 6.12.* (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "value": "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."
        }
      ],
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        "dateUpdated": "2026-08-22T15:32:57.113Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/afa58b7384913c8773d837acdb07b035690ec5d2"
        }
      ],
      "title": "net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74694",
    "datePublished": "2026-08-22T15:32:57.113Z",
    "dateReserved": "2026-08-15T05:44:03.926Z",
    "dateUpdated": "2026-08-22T15:32:57.113Z",
    "state": "PUBLISHED"
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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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/ncsi/ncsi-netlink.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"e60afa01d35f8b2671b27ca93309921427144cce\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"67c72b8ef63d9d9a610546fda30b116638f39745\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"4489b4a17892750131e4bef4bc1d3d703c8fb5ba\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"43c7d0a6917751ea898ae584d00f24f5deac46d4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"b5231ad0b376b801ab8cf2962b182cc29deaedb3\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"02226af69362758046822840fc6a497f5de33f00\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"3a60b5af75abe8e3494ccd074fb4ae6e601a3e55\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392\",\"lessThan\":\"afa58b7384913c8773d837acdb07b035690ec5d2\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/ncsi/ncsi-netlink.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.20\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.20\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.265\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.216\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.152\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.104\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.45\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/02226af69362758046822840fc6a497f5de33f00\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3a60b5af75abe8e3494ccd074fb4ae6e601a3e55\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/43c7d0a6917751ea898ae584d00f24f5deac46d4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4489b4a17892750131e4bef4bc1d3d703c8fb5ba\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/67c72b8ef63d9d9a610546fda30b116638f39745\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/afa58b7384913c8773d837acdb07b035690ec5d2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b5231ad0b376b801ab8cf2962b182cc29deaedb3\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e60afa01d35f8b2671b27ca93309921427144cce\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-24T17:37:02+00:00",
      "cve": "CVE-2026-74694",
      "id": "CVE-2026-74694",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74694.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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.


Detection rules are retrieved from Rulezet.