CVE-2026-63407
CORS flaw lets JavaScript use stolen JWTs to read and modify Grav API content
Is CVE-2026-63407 being exploited?
Not confirmed. CVE-2026-63407 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.27% probability of exploitation in the next 30 days.
How severe is CVE-2026-63407?
CVE-2026-63407 is rated High. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63407?
Yes. A fix has been recorded for CVE-2026-63407. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63407 affect?
CVE-2026-63407 affects Grav CMS with Grav API Plugin < 1.0.0-rc.16, Headless Grav sites exposing /api/v1 endpoints. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63407?
Upgrade Grav API Plugin to 1.0.0-rc.16+ and restrict CORS; revoke/rotate exposed tokens.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Cross-origin JS can submit attacker-obtained JWTs to /api/v1, read authenticated responses and perform write ops — data exfiltration and account modification.
Immediate action required
- affected< 1.0.0-rc.16
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.