Unknown

CVE-2026-74494 — ksmbd: reject repeated SMB2 NEGOTIATE requests

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.

Published Aug 15, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+2

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.22%

ahead of 12% of scored CVEs · Oct 29, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 0b1390cf2b6b91723b37c0909dd123f7a5eba1a7≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < fd6a6c43f96b40a08a22ff62f08d194a49741c8a≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 81e21cb7bd1479bb5238e0004a7e0110452c610b≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 7fb8dbeb3f2868ae836ca12311d89aed16fc2927≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < a60b5da05e318d9a364dbac38c347c7f24e625e7≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 7e02cb30e8a1f5fc78cb10b220b06020e36d0bbe≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < cb469993b3a61a72653770856d37af616d72d05fversion 5.15	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 29, 2026 · 14 reading(s) · max 0.22%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 15, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

7 on the record

git.kernel.org/stable/c/fd6a6c43f96b40a08a22ff62f08d194a49741c8a
NIST National Vulnerability Database
git.kernel.org/stable/c/a60b5da05e318d9a364dbac38c347c7f24e625e7
NIST National Vulnerability Database
git.kernel.org/stable/c/cb469993b3a61a72653770856d37af616d72d05f
NIST National Vulnerability Database
git.kernel.org/stable/c/0b1390cf2b6b91723b37c0909dd123f7a5eba1a7
NIST National Vulnerability Database
git.kernel.org/stable/c/81e21cb7bd1479bb5238e0004a7e0110452c610b
NIST National Vulnerability Database
git.kernel.org/stable/c/7fb8dbeb3f2868ae836ca12311d89aed16fc2927
NIST National Vulnerability Database
git.kernel.org/stable/c/7e02cb30e8a1f5fc78cb10b220b06020e36d0bbe
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Unknown CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 2d
Unknown CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 2d
Unknown CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 2d
Unknown CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 2d
Unknown CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 2d
Unknown CVE-2026-99210 accel/rocket: clear rdev on device init failure 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-74494 is "ksmbd: reject repeated SMB2 NEGOTIATE requests", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.22% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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