CVE-2026-32308 json
OneUptime: Stored XSS via Mermaid Diagram Rendering (securityLevel: "loose")
published 2026-03-12 7 mo ago modified 2026-10-07 33 d ago also EUVD-2026-11720 , GHSA-wvh5-6vjm-23qh
- cvss
- 7.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 18%
- public exploits
- 0
- none known
Summary
OneUptime is a solution for monitoring and managing online services. Prior to 10.0.23, the Markdown viewer component renders Mermaid diagrams with securityLevel: "loose" and injects the SVG output via innerHTML. This configuration explicitly allows interactive event bindings in Mermaid diagrams, enabling XSS through Mermaid's click directive which can execute arbitrary JavaScript. Any field that renders markdown (incident descriptions, status page announcements, monitor notes) is vulnerable. This vulnerability is fixed in 10.0.23.
Patch / fix
- npm oneuptime 10.0.23
- hackerbay oneuptime 10.0.23
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/OneUptime/oneuptime/security/advisories/GHSA-wvh5-6vjm-23qh referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N |
| GitHub | 3.1 | 7.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | oneuptime | <10.0.23 |
10.0.23 |
Affected products
- OneUptime oneuptime
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/OneUptime/oneuptime/security/advisories/GHSA-wvh5-6vjm-23qh
web, exploit, mitigation, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-32308
advisory
-
github.com
/OneUptime/oneuptime
package
-
github.com
/OneUptime/oneuptime/releases/tag/10.0.23
web
Sources
- CVE List CVE-2026-32308
- GitHub Advisory GHSA-wvh5-6vjm-23qh
- NVD CVE-2026-32308
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.