CVE-2026-23891
Decidim has a Cross-site scripting (XSS) vulnerability via user name field
Decidim is a participatory democracy framework. In versions below 0.30.5 and 0.31.0.rc1 through 0.31.0, 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. This issue has been fixed in versions 0.30.5 and 0.31.1.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Decidim has a Cross-site scripting (XSS) vulnerability via user name field
Decidim is a participatory democracy framework. In versions below 0.30.5 and 0.31.0.rc1 through 0.31.0, 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. This issue has been fixed in versions 0.30.5 and 0.31.1.
- Record
CVE-2026-23891- CVSS 4.0
- 9.3 Critical
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 - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-22024
Decidim is a participatory democracy framework. In versions below 0.30.5 and 0.31.0.rc1 through 0.31.0, 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. This issue has been fixed in versions 0.30.5 and 0.31.1.
- Record
EUVD-2026-22024- CVSS 4.0
- 9.3 Critical
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-fc46-r95f-hq7g
Decidim has a cross-site scripting (XSS) in user name
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 and made by Secu Labs against Decidim financed by the city of Lausanne (Switzerland).
- Record
GHSA-fc46-r95f-hq7g- CVSS 4.0
- 9.3 Critical
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 - CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
Decidim is a participatory democracy framework. In versions below 0.30.5 and 0.31.0.rc1 through 0.31.0, 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. This issue has been fixed in versions 0.30.5 and 0.31.1.
- Record
CVE-2026-23891- CVSS 4.0
- 9.3 Critical
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/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 - CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
Decidim has a Cross-site scripting (XSS) vulnerability via user name field
Decidim is a participatory democracy framework. In versions below 0.30.5 and 0.31.0.rc1 through 0.31.0, 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. This issue has been fixed in versions 0.30.5 and 0.31.1.
- Record
CVE-2026-23891- CVSS 4.0
- 9.3 Critical
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 - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVGHSA-fc46-r95f-hq7g
Decidim has a cross-site scripting (XSS) in user name
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 and made by Secu Labs against Decidim financed by the city of Lausanne (Switzerland).
- Record
GHSA-fc46-r95f-hq7g- CVSS 4.0
- 9.3 Critical
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 - CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
decidim-coreRubyGems |
0.31.0.rc1 up to 0.31.0 | 0.31.0 |
decidim-coreRubyGems |
before 0.30.5 | 0.30.5 |
decidim-coreRubyGems |
0.31.0.rc1 up to 0.31.1, plus listed versions 0.31.00.31.0.rc2 |
0.31.1 |
decidim-coreRubyGems |
before 0.30.5, plus listed versions 0.0.10.0.1.alpha10.0.1.alpha20.0.1.alpha30.0.1.alpha4 Show 45 moreShow less0.0.1.alpha50.0.1.alpha60.0.1.alpha70.0.1.alpha80.0.1.alpha90.0.20.0.30.0.50.0.60.0.70.0.8.10.1.00.10.00.10.10.11.0.pre10.11.10.11.20.12.00.12.0.pre0.12.10.12.20.13.00.13.0.pre10.13.10.14.10.14.20.14.30.14.40.15.00.15.10.15.20.16.00.16.10.17.00.17.10.17.20.18.00.18.10.19.00.19.10.2.00.20.00.20.10.21.00.22.0 |
0.30.5 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-23891 is a critical vulnerability (CVSS 9.3) in Decidim, published April 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 29th percentile. Fixed in decidim-core 0.31.0.
References
github.com/decidim/decidim/security/advisories/GHSA-fc46-r95f-hq7g
nvd.nist.gov/vuln/detail/CVE-2026-23891
Left out here: 108 versions. The JSON record has them.