{"id":"CVE-2026-58657","title":"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","summary":"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() fa…","severity":"medium","cvss":4.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N","cwe":["CWE-79"],"vendor":"Grav","product":"Grav","affected":["Grav >= 2.0.0-rc.9 < 2.0.0"],"patched":["getgrav/grav 2.0.0"],"published":"2026-07-08","updated":"2026-10-08","sourceUpdated":"2026-10-08T16:17:23.383","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-58657","references":[{"url":"https://github.com/getgrav/grav/commit/6582166173bb8eb5869d96aea384e0e73777c94c","label":"disclosure@vulncheck.com"},{"url":"https://github.com/getgrav/grav/commit/e03d29aa0d3ece16d73c1ffccfa78df8bf5f28b8","label":"disclosure@vulncheck.com"},{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-ffmg-hfvg-jhg9","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/grav-stored-css-injection-via-markdown-image-resize-action","label":"disclosure@vulncheck.com"},{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-ffmg-hfvg-jhg9","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58657"},{"url":"https://github.com/advisories/GHSA-ffmg-hfvg-jhg9"}],"tags":["nvd","cve.org","exploit-available","ghsa","composer"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-07-08T14:21:29.168366Z"},"epss":0.00267,"epssPercentile":0.18703,"aliases":["GHSA-ffmg-hfvg-jhg9"],"ecosystem":"composer","ingestedAt":"2026-09-16T23:07:58.093Z","slug":"CVE-2026-58657","body":"## Overview\n\nGrav 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 <img style=...> 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-58657)\n\nAffected packages:\n\n- `getgrav/grav = 2.0.0-rc.9`\n\nPatched in:\n\n- `getgrav/grav 2.0.0`\n\nSource: https://github.com/advisories/GHSA-ffmg-hfvg-jhg9","depth":"twilight","depthScore":38,"depthScoreParts":{"impact":26.4,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":218126,"id":"CVE-2026-58657","ts":1791478412981,"field":"exploit_available","old":"false","new":"true"}]}