CVE-2026-66033
7.5 · HIGHOverview
CVE-2026-66033 is a high-severity vulnerability affecting libssh2 libssh2. It was published on July 24, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from libssh2. Update libssh2 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| libssh2 | libssh2 | 0 | Affected |
Frequently Asked Questions
What is CVE-2026-66033?
CVE-2026-66033 is a high-severity vulnerability affecting libssh2 libssh2. It was published on July 24, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-66033?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-66033?
Check the references section for vendor advisories and patches from libssh2. Update libssh2 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-66033?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-66033 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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