CVE-2026-74694 is a vulnerability in Linux Kernel
Published on August 22, 2026
net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length
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.
Products Associated with CVE-2026-74694
Want to know whenever a new CVE is published for Linux Kernel? stack.watch will email you.
Affected Versions
Linux:- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below e60afa01d35f8b2671b27ca93309921427144cce is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below 67c72b8ef63d9d9a610546fda30b116638f39745 is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below 4489b4a17892750131e4bef4bc1d3d703c8fb5ba is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below 43c7d0a6917751ea898ae584d00f24f5deac46d4 is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below b5231ad0b376b801ab8cf2962b182cc29deaedb3 is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below 02226af69362758046822840fc6a497f5de33f00 is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below 3a60b5af75abe8e3494ccd074fb4ae6e601a3e55 is affected.
- Version 9771b8ccdfa6dcb1ac5128ca7fe8649f3092d392 and below afa58b7384913c8773d837acdb07b035690ec5d2 is affected.
- Version 4.20 is affected.
- Before 4.20 is unaffected.
- Version 5.10.265, <= 5.10.* is unaffected.
- Version 5.15.216, <= 5.15.* is unaffected.
- Version 6.1.183, <= 6.1.* is unaffected.
- Version 6.6.152, <= 6.6.* is unaffected.
- Version 6.12.104, <= 6.12.* is unaffected.
- Version 6.18.45, <= 6.18.* is unaffected.
- Version 7.1.9, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.