CVE-2026-72701 (CVSS 3.7)

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.

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CVSS v3.1 Score

3.7

LOW

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

EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.08%

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-208 CWE-208

References

Other References

https://github.com/getgrav/grav/security/advisories/GHSA-38p6-h87p-r4cg https://www.vulncheck.com/advisories/grav-cms-before-timing-attack-via-verifynonce https://github.com/getgrav/grav/security/advisories/GHSA-38p6-h87p-r4cg

Frequently Asked Questions

What is CVE-2026-72701? +

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. It has a CVSS v3.1 base score of 3.7 (LOW).

How severe is CVE-2026-72701? +

CVE-2026-72701 has a CVSS v3.1 score of 3.7 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0018, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-72701? +

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.

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