---
id: CVE-2026-72701
title: >-
  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
summary: >-
  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
  …
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-208
vendor: getgrav
product: grav
affected:
  - grav < 2.0.16
patched:
  - getgrav/grav 2.0.16
published: '2026-08-25'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T15:10:00.207'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72701'
references:
  - url: 'https://github.com/getgrav/grav/security/advisories/GHSA-38p6-h87p-r4cg'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/grav-cms-before-timing-attack-via-verifynonce
    label: disclosure@vulncheck.com
  - url: 'https://github.com/getgrav/grav/security/advisories/GHSA-38p6-h87p-r4cg'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72701'
  - url: 'https://github.com/advisories/GHSA-38p6-h87p-r4cg'
  - url: >-
      https://github.com/getgrav/grav/commit/a076b9073abc51c1df924529d65773e44950c5c4
  - url: 'https://github.com/getgrav/grav/releases/tag/2.0.16'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - composer
epss: 0.00216
epssPercentile: 0.11962
aliases:
  - GHSA-38p6-h87p-r4cg
ecosystem: composer
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-27T14:53:40.236596Z'
ingestedAt: '2026-09-17T20:28:02.779Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-72701)

Affected packages:

- `getgrav/grav <= 2.0.15`

Patched in:

- `getgrav/grav 2.0.16`

Source: https://github.com/advisories/GHSA-38p6-h87p-r4cg