How severe is CVE-2026-55794?

No CVSS score has been assigned to CVE-2026-55794 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-55794?

CVE-2026-55794 affects the following packages: craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-55794?

Update craftcms/cms to 5.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55794 is resolved across your whole dependency graph.

How do I detect CVE-2026-55794 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-2026-55794 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2026-55794 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55794 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-2026-55794?

CVE-2026-55794 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 33th 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-2026-55794?

CVE-2026-55794 is classified as Code Injection (CWE-94), CWE-1336 (CWE-1336). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-55794 published, and has it been updated?

CVE-2026-55794 was published on July 1, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-55794 — craftcms/cms

Fix: craftcms/cms#18680

CVE-2026-55794 is a Code Injection vulnerability in craftcms/cms. A fix is available for craftcms/cms — see the affected versions and patch details below.

Craft CMS: Potential authenticated Remote Code Execution via referrer redirect

Also known asGHSA-f74w-488g-8x5r

Published

Jul 1, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-2026-55794.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

🐘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

Requirements:

Control panel access
Permissions to edit an entry

Details

Control panel users with the ability to edit entries can execute unsandboxed Twig code via the HTTP Referrer header.

The issue happens when a user is saving entries. Strings for a signed redirect URL are being compiled as a Twig template via renderObjectTemplate(), and while a sandboxed alternative already exists (renderSandboxedObjectTemplate()), it is not used in this case. This signed URL can be specified by users, as it is reflected in the “Referer” HTTP request header, which is under attacker control.

This has been fixed in Craft 5.10.0. Affected users should update to that version or higher to get the fix.

Resources

https://github.com/craftcms/cms/pull/18680

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 5.9.0&&< 5.10.0	5.10.0`composer require craftcms/cms:^5.10.0`

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 5.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55794 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

### Requirements: * Control panel access * Permissions to edit an entry ### Details Control panel users with the ability to edit entries can execute unsandboxed Twig code via the HTTP Referrer header. The issue happens when a user is saving entries. Strings for a signed redirect URL are being compiled as a Twig template via `renderObjectTemplate()`, and while a sandboxed alternative already exists (`renderSandboxedObjectTemplate()`), it is not used in this case. This signed URL can be specified by users, as it is reflected in the “Referer” HTTP request header, which is under attacker contr

O3 Security · Impact-Aware SCA

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