Out-of-bounds Read in Libssh2
CVE-2026-66034
libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publick…
Vulnerability class: Buffer Overflow
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Libssh2 — versions 0, a13bb6c773f0d55ad1628cede57e99803cd898d9
Weakness classification (CWE)
References
- disclosure@vulncheck.com (issue-tracking, patch)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-66034?
- CVE-2026-66034 is a high-severity vulnerability in Libssh2, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-07-24.
- How severe is CVE-2026-66034?
- High severity. CVSS v3 base score is 7.5 out of 10.