Vulnerability details

CVE-2026-110714

sahlberg libsmb2

libsmb2 through 6.2 Heap Out-of-Bounds Read via decode_acl Integer Underflow

CVSS 4.0

7.1High

Official description

libsmb2 through 6.2 contains an integer underflow vulnerability in decode_acl that allows malicious SMB servers to trigger heap out-of-bounds reads via crafted security descriptors. Attackers controlling a server or intercepting unsigned sessions can send an AclSize below 8 in a QUERY_INFO reply, bypassing ACE bounds checks and crashing the client.

CVSS scores

Score	Version	Source	Vector
7.1High	4.0	CVEProject cvelistV5 (CNA) (VulnCheck)	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`
6.5Medium	3.1	CVEProject cvelistV5 (CNA) (VulnCheck)	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`

Affected products

Vendor	Product	Versions	Source
sahlberg	libsmb2	v ≤ 6.2	CVEProject cvelistV5 (CNA)

References and advisories

https://hackmd.io/@haind-pwn/libsmb2-query-info-reply-oob-read technical-descriptionexploit
https://github.com/sahlberg/libsmb2/blob/d67e213a5c4e7e4969fd81f0b95e4ca5831fbba1/lib/smb2-data-security-descriptor.c#L266 technical-description
https://github.com/sahlberg/libsmb2/commit/523abe20be3207011a936db47f1d3bab79c05450 patch
https://github.com/sahlberg/libsmb2 product
https://www.vulncheck.com/advisories/libsmb2-through-6.2-heap-out-of-bounds-read-via-decode-acl-integer-underflow third-party-advisory

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Details

Published: 2026-10-14
Last updated: 2026-10-20
State: Published
Assigner (CNA): VulnCheck

Exploit prediction (EPSS)

0.53%

Probability of exploitation in 30 days

45.4%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: No
Exploitation: Proof of concept
Technical impact: Partial

Weaknesses (CWE)

CWE-191
Integer Underflow (Wrap or Wraparound)