CVE-2026-23891
HIGH8.7EPSS 0.05%Decidim has a cross-site scripting (XSS) in user name
Published: 4/13/2026Modified: 5/13/2026
Also known as:GHSA-fc46-r95f-hq7g
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).
Affected packages (1)
- RubyGems/decidim-core>= 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 |
References (6)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-23891
- PATCHhttps://github.com/decidim/decidim
- WEBhttps://github.com/decidim/decidim/releases/tag/v0.30.5
- WEBhttps://github.com/decidim/decidim/releases/tag/v0.31.1
- WEBhttps://github.com/decidim/decidim/security/advisories/GHSA-fc46-r95f-hq7g
- WEBhttps://github.com/rubysec/ruby-advisory-db/blob/master/gems/decidim-core/CVE-2026-23891.yml