How severe is CVE-2026-28784?

No CVSS score has been assigned to CVE-2026-28784 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-28784?

CVE-2026-28784 affects the following packages: craftcms/cms (Packagist), craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-28784?

Update craftcms/cms to 5.9.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28784 is resolved across your whole dependency graph.

How do I detect CVE-2026-28784 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-28784 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-28784 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-28784 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-28784?

CVE-2026-28784 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 51th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-28784?

CVE-2026-28784 is classified as CWE-1336 (CWE-1336). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-28784 published, and has it been updated?

CVE-2026-28784 was published on March 4, 2026 and was last updated on October 22, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-28784: cms RCE — Fixed in 5.9.0-beta.1

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-28784.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk+0.04%

Lower risk than most CVEs51th percentile — riskier than 51% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘craftcms/cms🐘craftcms/cms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Craft is a content management system (CMS). Prior to 5.8.22 and 4.16.18, it is possible to craft a malicious payload using the Twig map filter in text fields that accept Twig input under Settings in the Craft control panel or using the System Messages utility, which could lead to a RCE. For this to work, you must have administrator access to the Craft Control Panel, and allowAdminChanges must be enabled for this to work, which is against our recommendations for any non-dev environment. Alternatively, you can have a non-administrator account with allowAdminChanges disabled, but you have access to the System Messages utility. Users should update to the patched versions (5.8.22 and 4.16.18) to mitigate the issue.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 5.0.0-RC1&&< 5.9.0-beta.1	5.9.0-beta.1`composer require craftcms/cms:^5.9.0-beta.1`
🐘Packagist	`craftcms/cms`	≥ 4.0.0-RC1&&< 4.17.0-beta.1	4.17.0-beta.1`composer require craftcms/cms:^4.17.0-beta.1`

Affected Products

1 product · 8 configurations

Application

craft cmscraftcms

> 5.0.0 && < 5.9.0

2 versions

4.0.05.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/cms to 5.9.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28784 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Craft is a content management system (CMS). Prior to 5.8.22 and 4.16.18, it is possible to craft a malicious payload using the Twig map filter in text fields that accept Twig input under Settings in the Craft control panel or using the System Messages utility, which could lead to a RCE. For this to work, you must have administrator access to the Craft Control Panel, and allowAdminChanges must be enabled for this to work, which is against our recommendations for any non-dev environment. Alternatively, you can have a non-administrator account with allowAdminChanges disabled, but you have access

O3 Security · Impact-Aware SCA

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CVE-2026-28784 — cms