CVEvulnerability

CVE-2026-66034

7.7 HIGH Published 2026-07-24 Modified 2026-07-30 Official page ↗
Status
Analyzed
Published
2026-07-24
Last modified
2026-07-30
Assigner
[email protected]
CVSS 4.0 ([email protected])
7.7 HIGH — CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Weaknesses
CWE-125, CWE-908

Description

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 publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.

Affected configurations

• libssh2 libssh2 (<= 1.11.1)

Related

Weakness · CWE (2)

  • CWE-125 Out-of-bounds Read weakness
  • CWE-908 Use of Uninitialized Resource weakness

References