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TI-2026-64827 Aliases CVE-2026-100671GHSA-jcv9-gfgx-wjw4

Grav before 2.0.25 Session Cookie Theft via Twig Sandbox

Priority HIGH 72CWE-200Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Information disclosure
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-200.

Summary

Grav is a flat-file CMS. In versions 2.0.19 through 2.0.24 — and in 2.0.0 through 2.0.18 and 1.7.x only where content Twig has been explicitly enabled — page content authored by a user holding only page-write permission is rendered through a Twig sandbox that allowlists get_cookie(), which returns any cookie sent with the current request, including the visitor's session cookie. Because the read occurs server-side via filter_input(INPUT_COOKIE, ...), the HttpOnly, Secure and SameSite attributes offer no protection. Grav then stores the finished post-Twig output in a page-content cache keyed only on page identity and the configuration checksum, with no session, user or request dimension and no bypass for authenticated visitors. A page published by a page-write user can therefore capture the session identifier of the next administrator who views it, after which the cached output serves that identifier to unauthenticated visitors, who can replay the cookie to authenticate as that administrator. Since 2.0.19, security.twig_content.process_enabled defaults to true and Security::applyTwigContentDefault() derives each page's process.twig flag from that gate, so content Twig runs on every page with no frontmatter or operator action. Fixed in 2.0.25; 1.7.x is outside the backport scope.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00367 30th percentileScored 2026-11-07
Fix Fixed grav (getgrav): 2.0.25

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

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 2.0.252.0.25Patch availableCNA
  • grav Vendorgetgrav Affected before 2.0.25 Fixed in 2.0.25 Patch available CNA

Remediation

  • Fix · CNA grav (getgrav) Fixed in 2.0.25

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    getgrav grav 2.0.25

    4 records Highest priority Priority HIGH 3 HIGH, 1 LOW

    Other records, highest priority first

    • TI-2026-64825 Grav before 2.0.25 Sensitive File Disclosure via Case-Variation BypassPriority HIGH 77
    • TI-2026-64826 Grav CMS 2.0.14 through 2.0.24 Privilege Escalation via Blueprint Guard BypassPriority HIGH 73
    • TI-2026-64824 Grav before 2.0.25 Sandbox Escape via array FilterPriority LOW 31
    Show all 4 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-100671
  2. 2026-10-03 Alias added: GHSA-jcv9-gfgx-wjw4

References

Advisory 1

  • 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