Discourse: Stored XSS in discourse-ai shared conversations onebox

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-32243
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-31 18:16:49 UTC
Updated2026-04-01 14:24:02 UTC
DescriptionDiscourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted conversation titles. This payload would execute in the browser of any user viewing the onebox preview, potentially allowing session hijacking or unauthorized actions on behalf of the victim. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Risk And Classification

Primary CVSS: v4.0 5.3 MEDIUM from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000470000 probability, percentile 0.144070000 (date 2026-04-01)

Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary5.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED5.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Discourse Discourse affected >= 2026.1.0-latest, < 2026.1.3 Not specified
CNA Discourse Discourse affected >= 2026.2.0-latest, < 2026.2.2 Not specified
CNA Discourse Discourse affected >= 2026.3.0-latest, < 2026.3.0 Not specified

References

ReferenceSourceLinkTags
github.com/discourse/discourse/security/advisories/GHSA-pjc5-8x3w-rfwx [email protected] github.com
github.com/discourse/discourse/commit/cac7d618a562ce934f8dbf73cdb70066a4... [email protected] github.com
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