CVE-2026-23891
Decidim has a cross-site scripting (XSS) in user name
Description
### Impact A stored code execution vulnerability in the user name field allows a low-privileged attacker to execute arbitrary code in the context of any user who passively visits a comment page, resulting in high confidentiality and integrity impact across security boundaries. ### Patches N/A ### Workarounds Not available ### References OWASP ASVS v4.0.3-5.1.3 ### Credits This issue was discovered in a security audit organized by [octree](https://octree.ch/) and made by [Secu Labs](https://seculabs.ch/) against Decidim financed by the city of Lausanne (Switzerland).
How to fix CVE-2026-23891
To remediate CVE-2026-23891, upgrade the affected package to a fixed version below.
- —upgrade to 0.31.1 or later
Is CVE-2026-23891 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 0.31.0.rc1, < 0.31.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L |
| osv | CVSS 3.1 | HIGH8.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N |