Executive brief
harp is a static web server that serves files to clients. Due to a rendering engine misconfiguration, the server failed to sanitize HTML output, allowing attackers to inject arbitrary JavaScript code. An attacker could craft malicious files that, when processed by harp, would execute JavaScript in the context of clients visiting the served pages, potentially leading to session hijacking, credential theft, or malware distribution.
Technical details
The vulnerability is a cross-site scripting (XSS) flaw in harp's HTML rendering engine. The root cause is the failure to sanitize HTML output when processing files, allowing attackers to inject arbitrary JavaScript that executes in the context of clients. The attack requires the ability to place or influence malicious files on a server running harp; no network-level authentication bypass is needed, but the attacker must have file control or influence over harp's input. All versions of harp are reported affected. The advisory was withdrawn in 2021 by the maintainer on the grounds that, as a static web server, an XSS classification was deemed inappropriate—suggesting the vulnerability may have been misclassified or the risk reconsidered.
Affected products
- harp harp all versions
Timeline
- 2020-09-02: disclosed
- 2021-06-01: other: Advisory withdrawn by maintainer