{"id":"CVE-2026-58657","summary":"Grav - Stored CSS Injection via Markdown Image resize() Action","details":"Grav before 2.0.0 (affected through 2.0.0-rc.9 and the 2.0 branch) contains a stored CSS injection vulnerability in the Markdown image resize() media action. Prior media hardening rejects direct ?style= payloads and unsafe attribute() fallbacks, but the resize() action in Excerpts::processMediaActions() writes caller-controlled values directly into the image's styleAttributes. A lower-privileged content editor who can edit page Markdown can store a crafted image URL with semicolon-delimited CSS declarations in the resize parameters, which are rendered into the final \u003cimg style=...\u003e attribute when a higher-privileged reviewer/admin views the page or preview. This does not require JavaScript execution but enables UI redress/overlay and content-manipulation attacks (e.g., a full-viewport fixed overlay). Fixed in 2.0.0.","aliases":["GHSA-ffmg-hfvg-jhg9"],"modified":"2026-07-15T01:49:08.023469586Z","published":"2026-07-08T13:49:12.183Z","database_specific":{"cwe_ids":["CWE-79"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58657.json","cna_assigner":"VulnCheck"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58657.json"},{"type":"ADVISORY","url":"https://github.com/getgrav/grav/security/advisories/GHSA-ffmg-hfvg-jhg9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58657"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/grav-stored-css-injection-via-markdown-image-resize-action"},{"type":"FIX","url":"https://github.com/getgrav/grav/commit/6582166173bb8eb5869d96aea384e0e73777c94c"},{"type":"FIX","url":"https://github.com/getgrav/grav/commit/e03d29aa0d3ece16d73c1ffccfa78df8bf5f28b8"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/getgrav/grav","events":[{"introduced":"e03d29aa0d3ece16d73c1ffccfa78df8bf5f28b8"},{"fixed":"bb4022f44b882ca4615188f4da5a0d646cef02ce"}],"database_specific":{"extracted_events":[{"introduced":"2.0.0-rc.9"},{"fixed":"2.0.0"}],"source":"AFFECTED_FIELD"}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58657.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N"}]}