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libssh2

9 known vulnerabilities.

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  • High 7.5

    libssh2 Heap Buffer Overflow via ETM Cipher Negotiation

    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 ci…

  • High 7.5

    libssh2 Heap Out-of-Bounds Read via publickey subsystem

    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 lib…

  • High 7.5

    libssh2 Integer Underflow DoS via AES-GCM Cipher Negotiation

    libssh2 through 1.11.1, fixed in commit a2ed82d, contains a pre-authentication integer underflow vulnerability in the ssh2_cipher_crypt() function in src/openssl.c that allows a malicious SSH server to crash any connecting client by negotiating AES-GCM cipher…

  • High 8.8

    libssh2 Double-Free Heap Corruption via sftp_open()

    libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds …

  • High 7.0

    libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation

    libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication ove…

  • High 8.1
    CVE-2026-55200 Public exploit

    libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c

    libssh2 1.11.1, fixed in commit 97acf3d, contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length value…