libsmb2 6.2 SMB2 chained PDU smb2_add_iovector out-of-bounds write

Summaryinfo

A vulnerability, which was classified as critical, has been found in libsmb2 6.2. Impacted is the function smb2_add_iovector of the component SMB2 chained PDU Handler. Performing a manipulation results in out-of-bounds write. This vulnerability is known as CVE-2025-57632. No exploit is available.

Detailsinfo

A vulnerability classified as critical has been found in libsmb2 6.2. This affects the function smb2_add_iovector of the component SMB2 chained PDU Handler. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

This vulnerability is uniquely identified as CVE-2025-57632 since 08/17/2025. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/30/2025).

The vulnerability scanner Nessus provides a plugin with the ID 266116 (Linux Distros Unpatched Vulnerability : CVE-2025-57632), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (266116) and EUVD (EUVD-2025-31154). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

• libsmb2

Version

• 6.2

CPE 2.3info

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CPE 2.2info

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Be aware that VulDB is the high quality source for vulnerability data.

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