CVE-2026-62387: Grav < 1.0.0-rc.16 CORS Misconfiguration via API Plugin

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-17 · updated 2026-10-24
Weakness: CWE-942

Description

The Grav API plugin (getgrav/grav-plugin-api) before 1.0.0-rc.16 shipped Access-Control-Allow-Origin: * as its default CORS configuration on all responses, including authenticated endpoints and preflight (OPTIONS) responses. Because the plugin accepts credentials via the Authorization and X-API-Token headers (set programmatically by JavaScript rather than via cookies), an attacker who obtains a valid access token (e.g., via log leakage, Referer headers, browser history, or network capture) can issue fully authenticated cross-origin requests from any malicious website to read sensitive data and perform write operations as the token's user. Fixed in 1.0.0-rc.16.

Affected products

getgrav grav: before 1.0.0-rc.16 — fixed in 1.0.0-rc.16

How to fix

Upgrade to a fixed version: getgrav grav 1.0.0-rc.16. Check the vendor advisory for mitigations.

References

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