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CVE-2026-66033 on CTRL-OS 26.05

Aliases: CVE-2026-66033

Packages: libssh2

Status: Plausible

Advisory Information

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.

Updates

2026-07-31 18:05 CEST

Metadata changes:

  • Status for package libssh2: “Plausible”

2026-07-31 18:05 CEST

Metadata changes:

  • Status for package libssh2: “New”