Vulnerability-Lookup

GHSA-4WJ4-79RR-PVFF

Vulnerability from github – Published: 2026-07-08 15:32 – Updated: 2026-07-08 15:32

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 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.

Severity

4.8 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

4.8 (Medium)


                  
                    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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-58657"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-08T14:17:20Z",
    "severity": "MODERATE"
  },
  "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\u0027s 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.",
  "id": "GHSA-4wj4-79rr-pvff",
  "modified": "2026-07-08T15:32:02Z",
  "published": "2026-07-08T15:32:01Z",
  "references": [
    {
      "type": "WEB",
      "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": "WEB",
      "url": "https://github.com/getgrav/grav/commit/6582166173bb8eb5869d96aea384e0e73777c94c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/getgrav/grav/commit/e03d29aa0d3ece16d73c1ffccfa78df8bf5f28b8"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/grav-stored-css-injection-via-markdown-image-resize-action"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-58657 (GCVE-0-2026-58657)

Vulnerability from cvelistv5 – Published: 2026-07-08 13:49 – Updated: 2026-07-08 14:21

Title

Grav - Stored CSS Injection via Markdown Image resize() 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() 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.

Severity

4.8 (Medium)


                        
                          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

4.8 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

VulnCheck

References

4 references

URL	Tags
https://github.com/getgrav/grav/security/advisori…	vendor-advisory
https://github.com/getgrav/grav/commit/6582166173…	patch
https://github.com/getgrav/grav/commit/e03d29aa0d…	patch
https://www.vulncheck.com/advisories/grav-stored-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
Grav	Grav	Affected: 2.0.0-rc.9 , < 2.0.0 (semver) Unaffected: 2.0.0 (semver)

Date Public

2026-06-22 00:00

Credits

DavidCarliez

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-4WJ4-79RR-PVFF

CVE-2026-58657 (GCVE-0-2026-58657)

Tags

Sightings

Nomenclature