PT-2026-64381 · Libssh2 · Libssh2

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CVE-2026-66034

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Published

2026-07-24

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Updated

2026-07-24

CVSS v3.1

7.5

High

VectorAV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
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.

Fix

Use of Uninitialized Resource

Out of bounds Read

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Weakness Enumeration

Related Identifiers

CVE-2026-66034

Affected Products

Libssh2