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GHSA-2g8c-wcg8-r65c

Опубликовано: 24 июл. 2026
Источник: github
Github: Не прошло ревью
CVSS4: 8.7
CVSS3: 7.5

Описание

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 ciphers during handshake. Attackers can exploit the underflow in the expression computing blocksize minus aadlen minus authentication tag length to trigger an out-of-bounds read and a memcpy call with a near-SIZE_MAX length argument, causing immediate process crash before any authentication occurs.

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 ciphers during handshake. Attackers can exploit the underflow in the expression computing blocksize minus aadlen minus authentication tag length to trigger an out-of-bounds read and a memcpy call with a near-SIZE_MAX length argument, causing immediate process crash before any authentication occurs.

EPSS

Процентиль: 31%
0.00386
Низкий

8.7 High

CVSS4

7.5 High

CVSS3

Дефекты

CWE-125

Связанные уязвимости

CVSS3: 7.5
ubuntu
7 дней назад

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 ciphers during handshake. Attackers can exploit the underflow in the expression computing blocksize minus aadlen minus authentication tag length to trigger an out-of-bounds read and a memcpy call with a near-SIZE_MAX length argument, causing immediate process crash before any authentication occurs.

CVSS3: 6.5
redhat
7 дней назад

A flaw was found in libssh2. A pre-authentication integer underflow vulnerability exists in the `ssh2_cipher_crypt()` function when negotiating AES-GCM ciphers during the handshake. A malicious SSH server can exploit this to trigger an out-of-bounds read and a memory copy operation with an extremely large length argument, leading to an immediate client process crash. This vulnerability results in a Denial of Service (DoS) for any connecting client.

CVSS3: 7.5
nvd
7 дней назад

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 ciphers during handshake. Attackers can exploit the underflow in the expression computing blocksize minus aadlen minus authentication tag length to trigger an out-of-bounds read and a memcpy call with a near-SIZE_MAX length argument, causing immediate process crash before any authentication occurs.

msrc
6 дней назад

libssh2 Integer Underflow DoS via AES-GCM Cipher Negotiation

CVSS3: 7.5
debian
7 дней назад

libssh2 through 1.11.1, fixed in commit a2ed82d, contains a pre-authen ...

EPSS

Процентиль: 31%
0.00386
Низкий

8.7 High

CVSS4

7.5 High

CVSS3

Дефекты

CWE-125