Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can send a crafted percent-encoded request path to a deployment using MG_ENABLE_DIRLIST and persuade a user to visit it. The mg_http_serve_dir() and listdir() path in src/http.c places the decoded request URI into the title and h1 elements without HTML entity encoding. The resulting reflected cross-site scripting executes in the Mongoose origin and can expose session data or perform actions as the victim. This issue is fixed in version 7.22.
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Fixes

Solution

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Workaround

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History

Thu, 20 Aug 2026 18:45:00 +0000

Type Values Removed Values Added
First Time appeared Cesanta
Cesanta mongoose
Vendors & Products Cesanta
Cesanta mongoose

Thu, 20 Aug 2026 17:45:00 +0000

Type Values Removed Values Added
Description Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can send a crafted percent-encoded request path to a deployment using MG_ENABLE_DIRLIST and persuade a user to visit it. The mg_http_serve_dir() and listdir() path in src/http.c places the decoded request URI into the title and h1 elements without HTML entity encoding. The resulting reflected cross-site scripting executes in the Mongoose origin and can expose session data or perform actions as the victim. This issue is fixed in version 7.22.
Title Mongoose: Reflected XSS via decoded URI in directory listing render
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-20T17:39:16.147Z

Reserved: 2026-08-11T17:18:01.598Z

Link: CVE-2026-73259

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-20T18:16:47.730

Modified: 2026-08-20T18:16:47.730

Link: CVE-2026-73259

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-20T18:30:03Z

Weaknesses