Impact
The vulnerability arises from the lws_ssh_parse_plaintext function in the libwebsockets SSH Protocol Handler, where an attacker can manipulate the msg_len argument to trigger unbounded resource consumption. This leads to excessive memory and CPU usage, effectively denying service to legitimate users. The weakness is classified as a resource exhaustion flaw (CWE‑400) and a missing resource management issue (CWE‑404).
Affected Systems
The issue affects the warmcat libwebsockets component in all versions up to and including 4.5.8. The vulnerability is present in the SSH Protocol Handler plugin distributed with the library.
Risk and Exploitability
The CVSS score of 6.9 indicates moderate severity, yet the flaw can be exploited remotely, allowing attackers to send crafted SSH packets that overwhelm the target. While the EPSS score is not available, the vulnerability has an exploitable proof‑of‑concept available and is not yet listed in CISA’s KEV catalog. The potential impact is a temporary denial of service for services that rely on libwebsockets for SSH handling, with the attacker only needing network access to the affected service.
OpenCVE Enrichment