CVE-2026-27570 json
Discourse Vulnerable to Stored XSS via Shared AI Conversation Onebox
published 2026-03-19 7 mo ago modified 2026-09-08 2 mo ago also BIT-discourse-2026-27570 , EUVD-2026-13192 , GHSA-hfxw-89hw-vwmv
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
Summary
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the onebox method in the SharedAiConversation model renders the conversation title directly into HTML without proper sanitization. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, tighten access by changing the `ai_bot_public_sharing_allowed_groups` site setting.
Patch / fix
- bitnami discourse 2026.1.2, 2026.2.1, 2026.3.0
- discourse discourse 2026.1.2, 2026.2.1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 5.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/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 |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | discourse | >=2026.1.0, <2026.1.2 >=2026.2.0, <2026.2.1 >=2026.3.0, <2026.3.0 |
2026.1.2 2026.2.1 2026.3.0 |
Affected products
- discourse discourse
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/discourse/discourse/commit/43a5a60b595f0120e6adfc131f2408508fe341f1
patch
-
github.com
/discourse/discourse/commit/c14f8f52b7999328bd9f8665f2ecfa24dadc4bf1
patch
-
github.com
/discourse/discourse/commit/f2aafa5c7467c94fcd4ebd36785a98e77ca088cc
patch
-
github.com
/discourse/discourse/security/advisories/GHSA-hfxw-89hw-vwmv
vendor-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-27570
web
Sources
- CVE List CVE-2026-27570
- NVD CVE-2026-27570
- OSV BIT-discourse-2026-27570
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.