Skip to content
Critical Vulnerabilities in libssh2 Enable Remote Code Execution and DoS Attacks

Critical Vulnerabilities in libssh2 Enable Remote Code Execution and DoS Attacks

First seen 22 Jun 2026, 13:39 UTC

Article Content

Browse articles
ThreatCluster AI
ThreatCluster June 23, 2026 at 13:16 UTC
  • Two critical vulnerabilities in libssh2 allow remote code execution and denial-of-service attacks.
  • CVE-2026-55200 has a CVSS score of 9.2, while CVE-2026-55199 scores 8.2.
  • Patches exist but are not yet officially released, leaving many systems at risk.

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.

Start a free Starter trial for enhanced analysis

Ask AI about this cluster

Updated 90d ago How this analysis works

Timeline

2026-06-17
CVE-2026-55199 and CVE-2026-55200 published
Two critical vulnerabilities in libssh2 were disclosed, impacting versions up to 1.11.1.
Cybernews
2026-06-22
Patches made available on GitHub
Developers provided fixes for the vulnerabilities via GitHub commits, but no official version has been released yet.
Heise.De
Recent
No active exploitation reported
As of the latest reports, there are no indications that attackers are actively exploiting the vulnerabilities.
Heise.De

More articles in this cluster (22)

Following this threat?

Track CVE-2026-55199 in your own feed — you're alerted when they show up in new reporting, leak sites or exploitation.

Free account · no card needed