What’s Vulnerable › Vulnerabilities

CVE-2026-110714: libsmb2 through 6.2 Heap Out-of-Bounds Read via decode_acl Integer Underflow

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-14 · updated 2026-10-20
• Weakness: CWE-191

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.

Affected products

• sahlberg libsmb2: through 6.2

References

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

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