{"id":"CVE-2026-117874","kind":"vulnerability","aliases":["CVE-2026-117874"],"related":[],"title":"Firefox: use-after-free in Internationalization component fixed in 159","description":"Use-after-free in the Internationalization component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.","summary":"A use-after-free bug in the Internationalization component of Firefox lets memory be reused after it is freed. The sources do not say what an attacker can achieve with it.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["desktop-browsers","firefox","runtime"],"not_affected_if":[],"how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`, and compare it with the fixed releases `159`, `115.44` ESR and `153.6` ESR.","fix":"- Update Firefox to `159` or later on the regular channel.\n- Update Firefox ESR to `115.44` or `153.6` (or later) on the ESR channel.","status":"open","published_at":"2026-10-27T14:16:41+00:00","first_seen_at":"2026-10-27T14:32:21+00:00","triaged_at":"2026-10-27T14:39:10+00:00","updated_at":"2026-10-27T14:39:10+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-27T14:39:10Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later on the regular channel.\n- Update Firefox ESR to `115.44` or `153.6` (or later) on the ESR channel.","reach":"unknown","title":"Firefox: use-after-free in Internationalization component fixed in 159","impact":"high","summary":"A use-after-free bug in the Internationalization component of Firefox lets memory be reused after it is freed. The sources do not say what an attacker can achieve with it.","category":"runtime","nicknames":[],"who_cares":["firefox","desktop-browsers"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown; use-after-free may allow memory corruption and code execution","analyst_note":"Check the Mozilla security advisory for Firefox 159 and ESR 115.44/153.6 for the trigger, exploitability and whether it is reachable from web content.","how_to_check":"- Check the installed Firefox version in the browser's About page or with `firefox --version`, and compare it with the fixed releases `159`, `115.44` ESR and `153.6` ESR.","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Anyone running an affected Firefox release on desktop or Android is exposed; the sources do not describe the exact trigger. Systems that run only a managed or already-updated Firefox build should confirm the version in their fleet. The sources do not say who can skip it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000588,"input_tokens":3244,"output_tokens":527,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117874':14A,17A '-2026':13A,16A '115.44':70C '153.6':74C '159':11A,67C 'achiev':52B 'attack':50B 'browser':20B 'bug':28B 'compon':8A,32B,60C 'cve':12A,15A 'desktop':19B 'desktop-brows':18B 'esr':69C,73C 'firefox':1A,21B,34B,66C,68C,72C 'fix':9A,64C 'free':5A,27B,56C 'freed':42B 'internation':7A,31B,59C 'let':35B 'memori':36B 'reus':38B 'runtim':22B 'say':47B 'sourc':44B 'use':3A,25B,54C 'use-after-fre':2A,24B,53C 'vulner':62C","nicknames":[],"mitigations":[],"who_affected":"Anyone running an affected Firefox release on desktop or Android is exposed; the sources do not describe the exact trigger. Systems that run only a managed or already-updated Firefox build should confirm the version in their fleet. The sources do not say who can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:41+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117874","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117874","severity":null,"published_at":"2026-10-27T14:16:41+00:00","modified_at":"2026-10-27T14:16:41+00:00","first_seen_at":"2026-10-27T14:32:21+00:00","fetched_at":"2026-10-27T14:32:21+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"}