CVE-2026-63407
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-63407 is a high-severity Permissive Cross-domain Security Policy with Untrusted Domains (CWE-942) vulnerability. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 19th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SC-7 (Boundary Protection) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-62545
Vulnerability Data
Grav API Plugin is a RESTful API for Grav CMS that provides full headless access to your site's content. Prior to 1.0.0-rc.16, the Grav API plugin CorsMiddleware returns Access-Control-Allow-Origin: * and permissive OPTIONS responses for authenticated /api/v1 endpoints. JavaScript from…
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any origin can submit an attacker-obtained JWT through the Authorization or X-API-Token header, read the authenticated response, and perform write operations with the token owner's privileges, enabling data exfiltration and account modification. This issue is fixed in version 1.0.0-rc.16.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V3.4.3V3.4.6V3.5.2
Mitigating Controls (NIST 800-53 r5) AI
Information flow enforcement requires approved authorizations and would reject policies permitting untrusted domains.
Boundary protection at external interfaces stops unauthorized cross-domain communication allowed by permissive policies.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Vulnerability identification processes can surface permissive policy misconfigurations.
Hardened configuration baselines and reviews directly prevent permissive CSP or cross-domain policies.
Secure SDLC activities include review and testing of web security policies to avoid untrusted domains.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Network security policies can restrict cross-domain communication but do not specifically mandate strict CSP or cross-domain policy configuration.
Security of network services includes defining allowed endpoints, which can limit untrusted domains but does not directly address web-client policy files.
Web filtering can block untrusted domains at the network level, partially mitigating permissive cross-domain policies.
Application security requirements should specify secure CSP and cross-domain policy settings, directly addressing the weakness.
Secure architecture principles include defining trust boundaries, which can reduce permissive cross-domain allowances.
Secure coding practices require proper configuration of CSP and cross-domain policies to avoid untrusted domains.