{"id":"CVE-2026-117922","kind":"vulnerability","aliases":["CVE-2026-117922"],"related":[],"title":"Firefox: use-after-free in WebSockets networking lets attackers run code","description":"Use-after-free in the Networking: WebSockets component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.","summary":"A use-after-free bug in Firefox's WebSockets networking component can corrupt memory when a page or connection reuses freed memory. The sources do not say what an attacker can get beyond memory corruption.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","runtime"],"not_affected_if":["already-updated-firefox"],"how_to_check":"- Check the installed Firefox version in the About Firefox dialog or with `firefox --version`; affected builds are older than `159`, `115.44` ESR, and `153.6` ESR.\n- Check whether the Firefox ESR branch in use is `115` or `153` and compare against the fixed `115.44` or `153.6`.","fix":"- Update Firefox to `159` or later.\n- Update Firefox ESR 115 to `115.44` or later.\n- Update Firefox ESR 153 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":"2026-10-27T14:37:15+00:00","updated_at":"2026-10-27T14:37:15+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-27T14:37:15Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or later.\n- Update Firefox ESR 115 to `115.44` or later.\n- Update Firefox ESR 153 to `153.6` or later.","reach":"unknown","title":"Firefox: use-after-free in WebSockets networking lets attackers run code","impact":"high","summary":"A use-after-free bug in Firefox's WebSockets networking component can corrupt memory when a page or connection reuses freed memory. The sources do not say what an attacker can get beyond memory corruption.","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 Mozilla's Firefox 159 and ESR advisories for the CVE details, exploitation conditions and whether code execution is confirmed.","how_to_check":"- Check the installed Firefox version in the About Firefox dialog or with `firefox --version`; affected builds are older than `159`, `115.44` ESR, and `153.6` ESR.\n- Check whether the Firefox ESR branch in use is `115` or `153` and compare against the fixed `115.44` or `153.6`.","needs_analyst":true,"not_affected_if":["already-updated-firefox"],"who_is_affected":"Anyone running Firefox builds older than the fixed versions, including desktop installs and managed fleets pinned to an ESR branch. The sources do not say which WebSockets usage or configuration triggers the flaw, so the exposure of server-side or non-browser users is unknown.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000627,"input_tokens":3252,"output_tokens":604,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117922':15A,18A '-2026':14A,17A '115.44':77C '153.6':81C '159':74C 'attack':10A,53B 'beyond':56B 'browser':19B 'bug':28B 'code':12A 'compon':34B,67C 'connect':42B 'corrupt':36B,58B 'cve':13A,16A 'desktop':20B 'esr':76C,80C 'firefox':1A,21B,30B,73C,75C,79C 'fix':71C 'free':5A,27B,62C 'freed':44B 'get':55B 'let':9A 'memori':37B,45B,57B 'network':8A,33B,65C 'page':40B 'reus':43B 'run':11A 'runtim':22B 'say':50B 'sourc':47B 'use':3A,25B,60C 'use-after-fre':2A,24B,59C 'vulner':69C 'websocket':7A,32B,66C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox builds older than the fixed versions, including desktop installs and managed fleets pinned to an ESR branch. The sources do not say which WebSockets usage or configuration triggers the flaw, so the exposure of server-side or non-browser users is unknown.","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-2026-117922","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117922","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"}