{"id":"CVE-2026-86853","title":"A malicious webpage could repeatedly trigger external URL schemes, causing system prompts or external application launches","summary":"A malicious webpage could repeatedly trigger external URL schemes, causing system prompts or external application launches. This could make Firefox for iOS temporarily unusable until the page is closed. This vulnerability was fixed in Fi…","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L","cwe":["CWE-451"],"vendor":"Mozilla","product":"Firefox for iOS","affected":["firefox_for_ios"],"published":"2026-09-08","updated":"2026-09-08","sourceUpdated":"2026-09-08T19:07:12.210","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-86853","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1847631","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-89/","label":"security@mozilla.org"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-08T15:47:54.911455Z"},"ingestedAt":"2026-09-08T15:33:26.987Z","epss":0.00174,"epssPercentile":0.07205,"slug":"CVE-2026-86853","body":"## Overview\n\nA malicious webpage could repeatedly trigger external URL schemes, causing system prompts or external application launches. This could make Firefox for iOS temporarily unusable until the page is closed. This vulnerability was fixed in Firefox for iOS 155.1.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":3314,"id":"CVE-2026-86853","ts":1788885294615,"field":"cvss","old":null,"new":"4.3"},{"seq":3313,"id":"CVE-2026-86853","ts":1788885294615,"field":"severity","old":"none","new":"medium"}]}