CVE-2026-40869

Decidim is a participatory democracy framework. Starting in version 0.19.0 and prior to versions 0.30.5 and 0.31.1, a vulnerability allows any registered and authenticated user to accept or reject any amendments. The impact is on any users who have created proposals where the amendments feature is enabled. This also elevates the user accepting the amendment as the author of the original proposal as people amending proposals are provided coauthorship on the coauthorable resources. Versions 0.30.5 and 0.31.1 fix the issue. As a workaround, disable amendment reactions for the amendable component (e.g. proposals).

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/decidim/decidim/commit/1b99136a1c7aa02616a0b54a6ab88d12907a57a9	Patch
https://github.com/decidim/decidim/security/advisories/GHSA-w5xj-99cg-rccm	Mitigation Patch Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:decidim:decidim::::::ruby::*
	cpe:2.3:a:decidim:decidim::::::ruby::*

History

No history.

Information

Published : 2026-04-21 20:17

Updated : 2026-06-17 10:45

NVD link : CVE-2026-40869

Mitre link : CVE-2026-40869

CVE.ORG link : CVE-2026-40869

JSON object : View

Products Affected

decidim

decidim

CWE

CWE-266

Incorrect Privilege Assignment

{"id": "CVE-2026-40869", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-40869", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-21T19:35:49.007349Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "decidim", "product": "decidim", "versions": [{"status": "affected", "version": ">= 0.31.0.rc1, < 0.31.1"}, {"status": "affected", "version": ">= 0.19.0, < 0.30.5"}]}]}], "published": "2026-04-21T20:17:00.207", "references": [{"url": "https://github.com/decidim/decidim/commit/1b99136a1c7aa02616a0b54a6ab88d12907a57a9", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/decidim/decidim/security/advisories/GHSA-w5xj-99cg-rccm", "tags": ["Mitigation", "Patch", "Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-266"}]}], "descriptions": [{"lang": "en", "value": "Decidim is a participatory democracy framework. Starting in version 0.19.0 and prior to versions 0.30.5 and 0.31.1, a vulnerability allows any registered and authenticated user to accept or reject any amendments. The impact is on any users who have created proposals where the amendments feature is enabled. This also elevates the user accepting the amendment as the author of the original proposal as people amending proposals are provided coauthorship on the coauthorable resources. Versions 0.30.5 and 0.31.1 fix the issue. As a workaround, disable amendment reactions for the amendable component (e.g. proposals)."}], "lastModified": "2026-06-17T10:45:47.800", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:decidim:decidim:*:*:*:*:*:ruby:*:*", "vulnerable": true, "matchCriteriaId": "866F9266-B876-4727-A253-D1F3B0456C43", "versionEndExcluding": "0.30.5", "versionStartIncluding": "0.19.0"}, {"criteria": "cpe:2.3:a:decidim:decidim:*:*:*:*:*:ruby:*:*", "vulnerable": true, "matchCriteriaId": "029260FC-BDC7-4FFF-B8DA-B7BF1BF978EC", "versionEndExcluding": "0.31.1", "versionStartIncluding": "0.31.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}