Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-72701Grav CMS before 2.0.16 Timing Attack via verifyNonce

Low 3.7

In plain English

A low-severity security flaw in grav from getgrav. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.7Low

Exploit odds (30 days)0.2%top 87.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Grav CMS before 2.0.16 contains a timing vulnerability in Utils::verifyNonce() that uses non-constant-time string comparison with the === operator instead of hash_equals() for CSRF nonce validation. Attackers can measure response timing differences to recover valid nonce values byte-by-byte through multiple requests, weakening CSRF protection below its intended security margin.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	getgrav/grav	2.0.16	GHSA-38p6-h87p-r4cg

Affected products (as reported)

Vendor	Product	Versions
getgrav	grav	0 – before 2.0.16

Weakness: CWE-208 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References

GitHub Security Advisory (GHSA-38p6-h87p-r4cg) vendor-advisory
VulnCheck Advisory: Grav CMS before 2.0.16 Timing Attack via verifyNonce third-party-advisory