CVE-2026-64257

Medium

Elevated severity or exploit probability.

CVSS base

9.1 CRITICAL

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

EPSS — probability of exploitation (30 days)

0.7%

50.2th percentile

CISA KEV

Not listed

Weakness / dates

—

Published 2026-07-25 · modified 2026-08-17

CVSS breakdown

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

Attack Vector	N	Network
Attack Complexity	L	Low
Privileges Required	N	None
User Interaction	N	None
Scope	U	Unchanged
Confidentiality	H	High
Integrity	N	None
Availability	H	High

Timeline

2026-07-25 — Published (NVD)
2026-08-17 — Last modified (NVD)

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions.

Affected

linux

References

Official: NVD · CVE.org