libsmb2 6.2+ is vulnerable to Buffer Overflow.

published 2025-09-25 13 mo ago modified 2026-11-05 3 d ago also EUVD-2025-31154

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits: 0; none known

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.

Patch / fix

distros 1 links 1

libsmb2 Debian 13 6.2+dfsg-2+deb13u1
libsmb2 Debian 14 6.2+dfsg-3

debian advisories DEBIAN-CVE-2025-57632

github.com/sahlberg/libsmb2@5e75eeb commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 13 mo ago (2025-09-26)

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input

References

Sources

CVE List CVE-2025-57632
NVD CVE-2025-57632

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary