Critical libssh2 Vulnerability Allows Attackers to Execute Remote Code Via Malicious SSH packets

Cybersecuritynews •Abinaya • June 23, 2026

A critical security vulnerability has been identified in the widely used libssh2 library, allowing remote attackers to execute arbitrary code through specially crafted SSH packets. The flaw, tracked as CVE-2026-55200, carries a CVSS score of 9.2 and is classified under CWE-680 (Integer Overflow to Buffer Overflow). Disclosed on June 17, 2026, the vulnerability affects libssh2 […]

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Critical Vulnerabilities in libssh2 Enable Remote Code Execution and DoS Attacks Two critical vulnerabilities have been discovered in libssh2, a widely used SSH library, affecting versions up to 1.11.1. The first vulnerability, CVE-2026-55200, allows remote code execution through crafted SSH packets, with a CVSS score of 9.2. The second vulnerability, CVE-2026-55199, enables denial-of-service attacks by causing client CPU exhaustion. Both vulnerabilities can be exploited without user interaction or authentication, posing a significant risk to systems using libssh2 for remote management. Patches are available in the form of GitHub commits, but a new official release has not yet been issued. The vulnerabilities could impact millions of systems globally, including routers, IoT devices, and servers. As of now, there are no reports of active exploitation. 19 sources 68

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Critical libssh2 Vulnerability Allows Attackers to Execute Remote Code Via Malicious SSH packets

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