CVE-2026-73259

MEDIUMCVSS 5.4/10EPSS 0.23%

Last modified

CVE-2026-73259 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. 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. EPSS estimates a 0.23% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.23%

13.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
cesantamongoose< 7.22

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-73259?
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.
How severe is CVE-2026-73259?
CVE-2026-73259 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.
How do I fix CVE-2026-73259?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST