Description (CNA)
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.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| libssh2 / libssh2 | affected 0 through 1.11.1; unaffected a2ed82d40964bbc0d64cd717aa0a5a892117d2e6 |
CWE
CWE-191, CWE-125
References
- https://github.com/libssh2/libssh2/pull/2401
- https://github.com/libssh2/libssh2/commit/a2ed82d40964bbc0d64cd717aa0a5a892117d2e6
- https://www.vulncheck.com/advisories/libssh2-integer-underflow-dos-via-aes-gcm-cipher-negotiation
ADP enrichment
No English description supplied.
No references supplied.