CVE-2026-55791: Craft CMS: Blind SSRF and Arbitrary JavaScript Injection via Host Header Poisoning in actionResourceJs

critical Affects craftcms/cms. Feed 2026.10.29.1, updated 2026-10-28; published 2026-06-19; advisory modified 2026-09-10.

Craft CMS: Blind SSRF and Arbitrary JavaScript Injection via Host Header Poisoning in actionResourceJs

Package: craftcms/cms Composer
Affected versions: >=5.0.0-RC1 and <5.10 or >=4.0.0-RC1 and <4.18
Fixed in: 5.10, 4.18
Severity: critical
Exploitation: not on CISA KEV · EPSS 0% (40.1th percentile)
Published: 2026-06-19
Source: osv.dev

References

CWE-346

NVD record craftcms/cms advisories

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