PT-2026-64382 · Libssh2 · Libssh2

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CVE-2026-66035

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Publicado

2026-07-24

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Atualizado

2026-07-24

CVSS v3.1

7.5

Alta

VetorAV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet length smaller than the cipher's block size during Encrypt-then-MAC cipher negotiation. In the fullpacket() function in src/transport.c, the ETM path allocates a buffer of packet length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk's SIZE field, enabling tcache bin confusion, overlapping live objects, and function pointer overwrite during the session handshake before authentication.

Correção

Heap Based Buffer Overflow

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Enumeração de Fraquezas

Identificadores relacionados

CVE-2026-66035

Produtos afetados

Libssh2