CVE-2026-89631
CVE CVE-2026-89631EUVD EUVD-2026-76543Published 2026-09-11T19:45:26.000ZLast changed 2026-09-13T06:32:09.000ZCVSS 9.1
What the advisory describes
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject a tree connect response whose byte count is too small CIFSTCon() bounds its strnlen() over the byte area with the server's ByteCount minus two, which for ByteCount 0 or 1 goes negative as an int and converts to a huge size_t. The later subtraction wraps the __u16 bytes_left, and that is what bounds cifs_strndup_from_utf16(): a bound of up to 65535 against a ~16 KB cifs_req_poolp object runs off the end of the slab object, and the bytes reach userspace through tcon->nativeFileSystem in /proc/fs/cifs/DebugData. Reject a byte area too small for what the parser consumes. Two bytes is the least it can consume, and no conformant response carries fewer. The new trace point is the 129th smb_eio_trace entry, which __mode(byte) cannot represent, so the attribute goes with it.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux cc20c031bb067eb3280a1c4b5c42295093e24863 <65deb18359341141d37dc86fc7853511be3c87a7; 2.6.30; patch: 6.18.51; cc20c031bb067eb3280a1c4b5c42295093e24863 <3be89e8039a85fa3b6cd5f9dcc4c1459eb356c2d; patch: 0; patch: 7.2.4; cc20c031bb067eb3280a1c4b5c42295093e24863 <411e484fe71a7f1028de617447edad9cb6d9d68a; patch: 7.3-rc1
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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