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TI-2026-40341 Aliases CVE-2026-55890GHSA-pmf8-g7c8-7v54

Grav: Stored CSS injection via Markdown image ?style=… reaches MediaObjectTrait::style()

Priority MEDIUM 55CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

Grav is a file-based Web platform. Prior to 2.0.0-rc.9, Grav's incomplete fix for stored XSS through the Markdown media attribute action (CVE-2026-42841) leaves the sibling MediaObjectTrait::style method reachable through the same Markdown excerpt-action pipeline, allowing an editor to save Markdown image style parameters that are written into the rendered img style attribute without sanitization. This issue is fixed in version 2.0.0-rc.9.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00503 43rd percentileScored 2026-11-07
Fix Fixed grav (getgrav): 2.0.0-rc.9getgrav/grav (Packagist): 2.0.0-rc.9

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
getgravgravbefore 2.0.0-rc.92.0.0-rc.9Patch availableCNA
—getgrav/grav (Packagist)before 2.0.0-rc.92.0.0-rc.9Patch availableGHSA-pmf8-g7c8-7v54
  • grav Vendorgetgrav Affected before 2.0.0-rc.9 Fixed in 2.0.0-rc.9 Patch available CNA
  • getgrav/grav (Packagist) Vendor— Affected before 2.0.0-rc.9 Fixed in 2.0.0-rc.9 Patch available GHSA-pmf8-g7c8-7v54

Remediation

  • Fix · CNA grav (getgrav) Fixed in 2.0.0-rc.9
  • Fix · GHSA-pmf8-g7c8-7v54 getgrav/grav (Packagist) Fixed in 2.0.0-rc.9 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55890
  2. 2026-10-03 Alias added: GHSA-pmf8-g7c8-7v54

References

Other 5

  • TI-2026-30893 Grav: Privilege Escalation via Missing Server-Side Validation of groups/access CVSS 3.1CRITICAL 9.4
  • TI-2025-28971 Cross Site Scripting vulnerability in grav v.1.7.48 and before allows an attacker to… CVSS 3.1CRITICAL 9.8
  • TI-2021-04523 Unauthenticated Arbitrary YAML Write/Update leads to Code Execution CVSS 3.1CRITICAL 9.8
  • TI-2026-50940 Grav CMS before 2.0.16 Origin Validation Bypass via Referer CVSS 4.0CRITICAL 9.3
  • TI-2026-46446 Grav before 2.0.7 Remote Code Execution via Blueprint dynamicData CVSS 4.0CRITICAL 9.3
  • TI-2021-22428 GravCMS 1.10.7 - Arbitrary YAML Write/Update (Unauthenticated) (2) CVSS 4.0CRITICAL 9.3
See all 228 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences