CVE-2026-23891: Decidim is a participatory democracy framework

Routine

HIGH 8.7UPGRADE

CVE-2026-23891 is a high-severity flaw (CVSS 8.7) 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. 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.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.7 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-04-13
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

2026-04-13 17:16 UTCPublished CVE record published
2026-06-17 10:22 UTCUpdated Record last modified

decidim decidim UPGRADE

Affected: < 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 0.31.0

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 0.31.0 (Debian / Ubuntu)

apt-cache madison decidim sudo apt install decidim=<VERSION_BEFORE_0.31.0> 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_0.31.0> 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-2026-23891?

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

Is CVE-2026-23891 being exploited?

CVE-2026-23891 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-2026-23891 affect?

CVE-2026-23891 affects decidim. Severity is high (CVSS 8.7). 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 o

How urgent is CVE-2026-23891?

Priority 38/100. High severity

Related CVEs

CVE-2026-40869 HIGH 7.5 UPGRADE Decidim is a participatory democracy framework

References

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