CVE-2026-28697: Craft CMS Vulnerable to Authenticated RCE via "craft.app.fs.write()" in Twig Templates

critical Affects craftcms/cms. Feed 2026.10.29.1, updated 2026-10-28; published 2026-03-03; advisory modified 2026-03-04.

Craft CMS Vulnerable to Authenticated RCE via "craft.app.fs.write()" in Twig Templates

Package: craftcms/cms Composer
Affected versions: >=5.0.0-RC1 and <5.9.0-beta.1 or >=4.0.0-RC1 and <4.17.0-beta.1
Fixed in: 5.9.0-beta.1, 4.17.0-beta.1
Severity: critical
Exploitation: not on CISA KEV · EPSS 1% (65.8th percentile)
Published: 2026-03-03
Source: osv.dev

References

CWE-1336

NVD record craftcms/cms advisories

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