Vulnerability · Published Jun 26, 2026 · Assigned by GitHub_M

CVE-2026-44696OpenProject: Stored CSS injection via Sanitize::Config::RELAXED[:css] enables phishing overlays and data exfiltration

Medium 5.7

In plain English

A medium-severity cross-site scripting in openproject from opf. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities).

Severity (CVSS 3.1)5.7Medium

Exploit odds (30 days)0.3%top 83.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

OpenProject is open-source, web-based project management software. Prior to 17.4.0, OpenProject's rich text (markdown) rendering pipeline uses Sanitize::Config::RELAXED[:css] for inline style sanitization. This configuration permits essentially all CSS properties in style attributes on permitted HTML elements (figure, img, table, th, tr, td). This allows any authenticated user with write access to formattable text fields (work package descriptions, comments, project descriptions, news) to inject CSS This vulnerability is fixed in 17.4.0.

Affected products (as reported)

Vendor	Product	Versions
opf	openproject	< 17.4.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N

References

https://github.com/opf/openproject/security/advisories/GHSA-j9q2-49mp-hmq5 x_refsource_CONFIRM