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

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.

Published Jun 26, 2026Updated Jun 27, 2026Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

chance of exploitation in 30 days

Affects

opf

openproject

CVSS base

5.7

MEDIUM

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

PoC

none · proof-of-concept · active

Automatable

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

opf

Products (1)

openproject

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
5.7	CVSS 3.1	MEDIUM	—	—	cvelistV5

Weakness & attack patterns

CWE-79

References

1 on the record

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

Elsewhere on this site

opfevery CVE for this vendor
CWE-79other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.