CVE-2026-74494ksmbd: reject repeated SMB2 NEGOTIATE requests
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: ksmbd: reject repeated SMB2 NEGOTIATE requests Unauthenticated client can send multiple successful SMB2 NEGOTIATE requests on one connection before SESSION_SETUP. While the connection is in KSMBD_SESS_NEED_SETUP, smb2_handle_negotiate() accepts another SMB3.1.1 NEGOTIATE and overwrites conn->preauth_info with a new allocation. Only the final allocation is freed when the connection is released, leaking one object for every additional successful request. A repeated SMB2 NEGOTIATE after a dialect has been selected is a protocol violation. MS-SMB2 section 3.3.5.4 requires the server to disconnect without replying in this case. Set the connection exiting when rejecting the request, in addition to suppressing the response. Reject SMB2 NEGOTIATE unless the connection is new or is waiting for the SMB2 NEGOTIATE that follows an SMB1 multi-protocol negotiate. Serialize both SMB1 and SMB2 negotiation paths under conn->srv_mutex, since they update connection-wide dialect and negotiation state. Move the locking contract to ksmbd_smb_negotiate_common(), where the state and dialect are selected, and add ksmbd_conn_new() for consistent state access.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Aug 23, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 0b1390cf2b6b91723b37c0909dd123f7a5eba1a7; from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before fd6a6c43f96b40a08a22ff62f08d194a49741c8a; from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 81e21cb7bd1479bb5238e0004a7e0110452c610b; from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 7fb8dbeb3f2868ae836ca12311d89aed16fc2927; from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before a60b5da05e318d9a364dbac38c347c7f24e625e7; from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before 7e02cb30e8a1f5fc78cb10b220b06020e36d0bbe; from e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 before cb469993b3a61a72653770856d37af616d72d05f | CNA record |
References
- https://git.kernel.org/stable/c/0b1390cf2b6b91723b37c0909dd123f7a5eba1a7
- https://git.kernel.org/stable/c/fd6a6c43f96b40a08a22ff62f08d194a49741c8a
- https://git.kernel.org/stable/c/81e21cb7bd1479bb5238e0004a7e0110452c610b
- https://git.kernel.org/stable/c/7fb8dbeb3f2868ae836ca12311d89aed16fc2927
- https://git.kernel.org/stable/c/a60b5da05e318d9a364dbac38c347c7f24e625e7
- https://git.kernel.org/stable/c/7e02cb30e8a1f5fc78cb10b220b06020e36d0bbe
- https://git.kernel.org/stable/c/cb469993b3a61a72653770856d37af616d72d05f
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.