PT-2026-56446 · Grav · Grav

Davidcarliez · Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-58657

Mitre

CVSS v3.1

4.8

Medium

Base vector

AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

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 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.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-58657

Affected Products

Grav

References · 5

• https://github.com/getgrav/grav/commit/e03d29aa0d3ece16d73c1ffccfa78df8bf5f28b8 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-58657 · Security Note
• https://github.com/getgrav/grav/commit/6582166173bb8eb5869d96aea384e0e73777c94c · Patch
• https://github.com/getgrav/grav/security/advisories/GHSA-ffmg-hfvg-jhg9 · Vendor Advisory
• https://vulncheck.com/advisories/grav-stored-css-injection-via-markdown-image-resize-action · Note