Grav < 1.0.0-rc.16 CORS Misconfiguration via API Plugin

published 2026-07-17 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-45087

cvss: 7.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

getgrav grav 1.0.0-rc.16

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 3 mo ago (2026-07-17)

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/getgrav/grav/security/advisories/GHSA-93px-98wh-6fj2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	7.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
CNA	3.1	7.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
CNA	4.0	7.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

getgrav grav

Classification

Weakness

CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains

References

github.com /getgrav/grav/security/advisories/GHSA-93px-98wh-6fj2
vendor-advisory, exploit
vulncheck.com /advisories/grav-rc-16-cors-misconfiguration-via-api-plugin
third-party-advisory

Sources

CVE List CVE-2026-62387
NVD CVE-2026-62387

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary