SecuriTricks - CVE-2025-57632

Description

libsmb2 6.2+ is vulnerable to Buffer Overflow. When processing SMB2 chained PDUs (NextCommand), libsmb2 repeatedly calls smb2_add_iovector() to append to a fixed-size iovec array without checking the upper bound of v->niov (SMB2_MAX_VECTORS=256). An attacker can craft responses with many chained PDUs to overflow v->niov and perform heap out-of-bounds writes, causing memory corruption, crashes, and potentially arbitrary code execution. The SMB2_OPLOCK_BREAK path bypasses message ID validation.

Product(s) Impacted

Vendor	Product	Versions
Libsmb2	Libsmb2	6.2-*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-120

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	libsmb2	libsmb2	6.2-*	/	/	/	/	/	/	/

References

https://gist.github.com/ZjW1nd/0b95b63307ceee7890e88e4abc6f041e

https://github.com/sahlberg/libsmb2

https://github.com/sahlberg/libsmb2/blob/master/lib/compat.c#L569

CVSS Score

7.5 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: HIGH

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

View Vector String

Timeline

Published: Sept. 25, 2025, 8:15 p.m.
Last Modified: Sept. 26, 2025, 9:15 p.m.

Status : Awaiting Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

cve@mitre.org

CVE-2025-57632