CVE-2026-72720

MEDIUM 6.4

Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing

CVSS Score

6.4

EPSS Score

0.0%

EPSS Percentile

0th

Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.format_for_email because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and hashtag data-slug values can cause decoded attribute text to be reinterpreted as HTML. The vulnerable conversion also fails to strictly validate the Vimeo iframe host and path, allowing non-Vimeo allowlisted iframes to be converted. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1.

CWE	CWE-79
Vendor	discourse
Product	discourse
Published	Aug 10, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

discourse / discourse

< 2026.1.7 >= 2026.6.0-latest, < 2026.6.2 >= 2026.7.0-latest, < 2026.7.1 >= 2026.8.0-latest, < 2026.8.0-latest.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗