CVE-2026-100671: Information Disclosure (CVSS 8)

Description

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.

Is your site exposed to CVE-2026-100671?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

8.0

HIGH

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

EPSS — Exploit Prediction

0.0029

Probability of exploitation

0.20%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-200 CWE-200

References

Other References

https://github.com/getgrav/grav/security/advisories/GHSA-pp89-h475-7gj6 https://www.vulncheck.com/advisories/grav-before-2.0.25-session-cookie-theft-via-twig-sandbox https://github.com/getgrav/grav/security/advisories/GHSA-pp89-h475-7gj6

Frequently Asked Questions

What is CVE-2026-100671? +

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. It has a CVSS v3.1 base score of 8.0 (HIGH).

How severe is CVE-2026-100671? +

CVE-2026-100671 has a CVSS v3.1 score of 8.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0029, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-100671? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-15625

Unauthenticated user is able to execute arbitrary SQL commands in Sparx Pro Cloud Server database in certain cases.

CVE-2026-22051

StorageGRID (formerly StorageGRID Webscale) versions prior to 11.9.0.13 and 12.0.0.6 are susceptible to a Information Disclosure vulnerability. Successful exploit could …

CVE-2026-41186

When Calico's shared debug server is enabled (disabled by default), the Calico kube-controllers and Goldmane components bind their Go pprof …

CVE-2026-54396

An information disclosure vulnerability exists in the MISP AuthKey edit functionality. When a validation error occurs during an AuthKey edit …

CVE-2026-13230

An information disclosure vulnerability was identified in TP-Link Kasa EC70 v4 and EC71 v4 in the local discovery mechanism, which …

CVE-2026-53912

Cerebrate before version 1.37 exposed credential material from self-registration requests. The self-registration workflow stored the registrant’s hashed password in the …

CVE-2026-100671