{"id":"CVE-2026-117916","kind":"vulnerability","aliases":["CVE-2026-117916"],"related":[],"title":"Firefox: use-after-free in XSLT component could let a page run code","description":"Use-after-free in the XSLT component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.","summary":"A use-after-free bug in the XSLT component of Firefox was fixed in Firefox 159 and Firefox ESR 153.6. Use-after-free flaws can let a crafted page corrupt memory and may allow an attacker to run code in the browser.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","runtime"],"not_affected_if":["already-updated-browser"],"how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`.\n- unknown for any other check; the sources do not say.","fix":"- Update Firefox to `159` or later.\n- Update Firefox ESR to `153.6` or later.","status":"open","published_at":"2026-10-27T14:16:47+00:00","first_seen_at":"2026-10-27T14:32:22+00:00","triaged_at":"2026-10-27T14:37:23+00:00","updated_at":"2026-10-27T14:37:23+00:00","category":"runtime","confidence":0.4,"triage":{"at":"2026-10-27T14:37:23Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later.\n- Update Firefox ESR to `153.6` or later.","reach":"internet","title":"Firefox: use-after-free in XSLT component could let a page run code","impact":"high","summary":"A use-after-free bug in the XSLT component of Firefox was fixed in Firefox 159 and Firefox ESR 153.6. Use-after-free flaws can let a crafted page corrupt memory and may allow an attacker to run code in the browser.","category":"runtime","nicknames":[],"who_cares":["firefox","browsers","desktop"],"confidence":0.4,"needs_auth":"no","worst_case":"Attacker may run code through a crafted page in the browser","analyst_note":"Confirm the exploitability and affected version range from the Mozilla security advisory and the NVD entry, since the sources give only the fixed versions.","how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`.\n- unknown for any other check; the sources do not say.","needs_analyst":true,"not_affected_if":["already-updated-browser"],"who_is_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions is potentially exposed, since the flaw is in the browser's XSLT processing and is triggered by visiting content. The sources do not say which configurations or builds are affected beyond that, so unknown for narrower scope.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000585,"input_tokens":3230,"output_tokens":523,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117916':17A,20A '-2026':16A,19A '153.6':45B,87C '159':41B,83C 'allow':60B 'attack':62B 'browser':21B,68B 'bug':30B 'code':14A,65B 'compon':8A,34B,76C 'corrupt':56B 'could':9A 'craft':54B 'cve':15A,18A 'desktop':22B 'esr':44B,86C 'firefox':1A,23B,36B,40B,43B,82C,85C 'fix':38B,80C 'flaw':50B 'free':5A,29B,49B,72C 'let':10A,52B 'may':59B 'memori':57B 'page':12A,55B 'run':13A,64B 'runtim':24B 'use':3A,27B,47B,70C 'use-after-fre':2A,26B,46B,69C 'vulner':78C 'xslt':7A,33B,75C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions is potentially exposed, since the flaw is in the browser's XSLT processing and is triggered by visiting content. The sources do not say which configurations or builds are affected beyond that, so unknown for narrower scope.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:47+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117916","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117916","severity":null,"published_at":"2026-10-27T14:16:47+00:00","modified_at":"2026-10-27T14:16:47+00:00","first_seen_at":"2026-10-27T14:32:22+00:00","fetched_at":"2026-10-27T14:32:22+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}