{"cve":"CVE-2020-26976","nvd":{"published":"2021-01-07T14:15:12.173","modified":"2026-06-17T03:08:39.220","status":"Modified","description":"When a HTTPS pages was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing. This vulnerability affects Firefox < 84.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","score":6.5},"cwes":[],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=1674343","https://lists.debian.org/debian-lts-announce/2021/02/msg00001.html","https://lists.debian.org/debian-lts-announce/2021/02/msg00002.html","https://security.gentoo.org/glsa/202102-02","https://www.debian.org/security/2021/dsa-4840"],"products":["debian:debian_linux","mozilla:firefox"],"source":"nvd","synced_at":"2026-10-19T21:12:09.559580076+00:00"},"epss":{"cve":"CVE-2020-26976","score":0.01639,"percentile":0.76366,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}