CVE-2026-40869: Decidim is a participatory democracy framework

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-40869 is a high-severity flaw (CVSS 7.5) affecting decidim. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 coauthors

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 87%)
CISA exploited list	No
Weakness	CWE-266
Published	2026-04-21
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: decidim

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 20:17 UTCPublished CVE record published
2026-06-17 10:45 UTCUpdated Record last modified

decidim decidim UPGRADE

Affected: >= 0.19.0 and < 0.30.5 · >= 0.31.0 and < 0.31.1

Fixed in: 0.30.5, 0.31.1

Safe to downgrade to: a release before 0.19.0

1. Check installed version

apt-cache policy decidim || rpm -q decidim || decidim --version

2. UPGRADE to 0.30.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade decidim

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade decidim

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.19.0 (Debian / Ubuntu)

apt-cache madison decidim sudo apt install decidim=<VERSION_BEFORE_0.19.0> sudo apt-mark hold decidim

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list decidim sudo dnf downgrade decidim-<VERSION_BEFORE_0.19.0> sudo dnf versionlock add decidim

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40869?

decidim: upgrade to 0.30.5, 0.31.1. Exact commands for each OS are on this page.

Is CVE-2026-40869 being exploited?

CVE-2026-40869 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40869 affect?

CVE-2026-40869 affects decidim. Severity is high (CVSS 7.5). 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

How urgent is CVE-2026-40869?

Priority 34/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-23891 HIGH 8.7 UPGRADE Decidim is a participatory democracy framework

References

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