CVE-2026-58657Grav - Stored CSS Injection via Markdown Image resize() Action
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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 <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.
- CVSS
- 4.8 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Grav Grav grav:grav (from the name) | from 2.0.0-rc.9 before 2.0.0; 2.0.0 not affected | CNA record |
References
- https://github.com/getgrav/grav/security/advisories/GHSA-ffmg-hfvg-jhg9vendor-advisory
- https://github.com/getgrav/grav/commit/6582166173bb8eb5869d96aea384e0e73777c94cpatch
- https://github.com/getgrav/grav/commit/e03d29aa0d3ece16d73c1ffccfa78df8bf5f28b8patch
- https://www.vulncheck.com/advisories/grav-stored-css-injection-via-markdown-image-resize-actionthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.