Integer overflow in Sahlberg Libsmb2
CVE-2026-115505
libsmb2 before 6.3 contains integer overflow vulnerabilities in the DCE/RPC NDR decoder in lib/dcerpc.c that allow heap out-of-bounds reads and writes. A malicious SMB server or machine-in-the-middle on unsigned connections can send crafted NetrShareEnum replies with wrapping actual_count or max_count values when clients call smb2_share_enum_async(), corrupting heap memory.
Vulnerability class: Integer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- hackmd.io/@haindpwn/libsmb2-dcerpc-ndr-count-overflow-oob (technical-description, exploit)
- github.com/sahlberg/libsmb2/issues/496 (issue-tracking)
- github.com/sahlberg/libsmb2/commit/a79f6914cb5ed3f74293d15cdea901261ce179ff (patch)
- github.com/sahlberg/libsmb2/releases/tag/libsmb2-6.3 (release-notes)
- github.com/sahlberg/libsmb2 (product)
- www.vulncheck.com/advisories/libsmb2-before-6.3-integer-overflow-in-dce-rpc-ndr… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-115505?
- CVE-2026-115505 is a high-severity vulnerability in Sahlberg Libsmb2, classified under Integer Overflow or Wraparound. CVSS score: 7.6/10. Published 2026-10-22.
- How severe is CVE-2026-115505?
- High severity. CVSS v3 base score is 7.6 out of 10.