Out-of-bounds Read The advisory has been revoked - it doesn't affect any version of package libssh2-devel (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS7-LIBSSH2DEVEL-18324281
- published27 Jul 2026
- disclosed24 Jul 2026
Introduced: 24 Jul 2026
CVE-2026-66033 (opens in a new tab)Amendment
The Centos security team deemed this advisory irrelevant for Centos:7.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libssh2-devel package and not the libssh2-devel package as distributed by Centos.
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.