How severe is CVE-2026-40869?

CVE-2026-40869 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-40869 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40869?

CVE-2026-40869 affects Decidim. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40869?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-40869 have an EU (EUVD) identifier?

Yes. CVE-2026-40869 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24251.

When was CVE-2026-40869 published?

CVE-2026-40869 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-40869

CVE-2026-40869 is a high-severity vulnerability in Decidim with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-266.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24251
Weakness: CWE-266
Affected product: Decidim
Published: 2026-04-21
Last modified: 2026-06-17

Description

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).

Frequently asked questions

What is 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).
How severe is CVE-2026-40869?: CVE-2026-40869 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-40869 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40869?: CVE-2026-40869 affects Decidim. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40869?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40869 have an EU (EUVD) identifier?: Yes. CVE-2026-40869 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24251.
When was CVE-2026-40869 published?: CVE-2026-40869 was published on 2026-04-21 and last updated on 2026-06-17.

References

Affected products (1)

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

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