Description
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.
Published: 2026-08-22
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

No vendor fix or workaround currently provided.

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History

Sat, 22 Aug 2026 18:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-787

Sat, 22 Aug 2026 15:45:00 +0000

Type Values Removed Values Added
Description 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.
Title net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-22T15:32:57.113Z

Reserved: 2026-08-15T05:44:03.926Z

Link: CVE-2026-74694

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-22T16:16:43.920

Modified: 2026-08-22T16:16:43.920

Link: CVE-2026-74694

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-22T18:15:03Z

Weaknesses