CVE-2026-66318
Origin validation bug in Microsoft Edge allows cross-origin info disclosure.
Is CVE-2026-66318 being exploited?
Not confirmed. CVE-2026-66318 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 0.24% probability of exploitation in the next 30 days.
How severe is CVE-2026-66318?
CVE-2026-66318 is rated High with a CVSS score of 8.1. 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-2026-66318?
Yes. A fix has been recorded for CVE-2026-66318. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-66318 affect?
CVE-2026-66318 affects Microsoft Edge (Chromium-based). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-66318?
Apply vendor patch when released; restrict untrusted sites and enforce CSP.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Origin validation bypass in Chromium-based Edge lets remote attackers exfiltrate cross-origin data over the network.
Patch when possible
- affected>= 1.0.0.0 and < 151.0.4129.59
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.