CVE-20XX-?
agent?

CVE-2026-89631

9.1 CRITICAL 0.5% exploit odds No fix listed Other OS & kernel

What it is

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.

At a glance

Exploitability
Can be exploited over the network without logging in. High risk of data exposure, service disruption.
Exploit odds
0.5% chance of exploitation in the next 30 days (EPSS).
Fix
No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

  1. ReservedThe CVE id was reserved by its CNA
  2. PublishedDisclosed publicly on CVE.org and NVD
  3. Last updatedMost recent change to the record

Why it ranks here

Details

Published
Last modified
Exploit probability
0.5% · EPSS, next 30 days
Record status
Received

Attack profile CVSS 3.1 · 9.1

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High
Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-89631.md and follow it. Check whether this project is affected by CVE-2026-89631. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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References

NVD record · CVE.org record