Out-of-bounds Write Affecting libssh2 package, versions [0,]
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
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-CONAN-LIBSSH2-17660954
- published28 Jun 2026
- disclosed17 Jun 2026
- creditUnknown
Introduced: 17 Jun 2026
CVE-2026-55200 (opens in a new tab)How to fix?
A fix was pushed into the master branch but not yet published.
Overview
Affected versions of this package are vulnerable to Out-of-bounds Write through the ssh2_transport_read function in transport.c when processing SSH packets with excessively large packet_length values. An attacker can corrupt heap memory and potentially execute arbitrary code by sending maliciously crafted SSH packets to the affected system.
Workaround
This vulnerability can be mitigated by implementing strict network access controls, ensuring clients only connect to trusted SSH servers, and using firewalls to block untrusted incoming connections if deployed as a server-side application.