{"id":"CVE-2026-117876","kind":"vulnerability","aliases":["CVE-2026-117876"],"related":[],"title":"Firefox: use-after-free in text layout and fonts code","description":"Use-after-free in the Layout: Text and Fonts 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 Layout: Text and Fonts component lets memory be reused after it is freed. An attacker who gets a user to load a crafted page could potentially crash the browser or run code in it.","severity":"high","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browsers","desktop","firefox","managed-fleet","runtime"],"not_affected_if":["already-updated-browser"],"how_to_check":"- Check the Firefox version with `firefox --version` or Help > About Firefox\n- Compare the installed version against the fixed releases listed in the fix field\n- unknown","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":"2026-10-27T14:16:42+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":0.6,"triage":{"at":"2026-10-27T14:39:10Z","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":"internet","title":"Firefox: use-after-free in text layout and fonts code","impact":"high","summary":"A use-after-free bug in Firefox's Layout: Text and Fonts component lets memory be reused after it is freed. An attacker who gets a user to load a crafted page could potentially crash the browser or run code in it.","category":"runtime","nicknames":[],"who_cares":["firefox","browsers","desktop","managed-fleet"],"confidence":0.6,"needs_auth":"no","worst_case":"Browser crash or code execution in the browser process after visiting a page","analyst_note":"Check the Mozilla advisory for this CVE to confirm whether exploitation is known and which Firefox builds are covered; the NVD entry gives only the fixed versions.","how_to_check":"- Check the Firefox version with `firefox --version` or Help > About Firefox\n- Compare the installed version against the fixed releases listed in the fix field\n- unknown","needs_analyst":true,"not_affected_if":["already-updated-browser"],"who_is_affected":"Any installed Firefox build older than the fixed versions is affected, so any browser on a user's desktop or a managed fleet. Managed teams should push the update through their normal browser channel. Sites and servers you run are not exposed through this flaw.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000596,"input_tokens":3256,"output_tokens":541,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117876':14A,17A '-2026':13A,16A '115.44':86C '153.6':90C '159':83C 'attack':48B 'browser':18B,62B 'bug':30B 'code':11A,65B 'compon':38B,76C 'could':58B 'craft':56B 'crash':60B 'cve':12A,15A 'desktop':19B 'esr':85C,89C 'firefox':1A,20B,32B,82C,84C,88C 'fix':80C 'fleet':23B 'font':10A,37B,75C 'free':5A,29B,69C 'freed':46B 'get':50B 'layout':8A,34B,72C 'let':39B 'load':54B 'manag':22B 'managed-fleet':21B 'memori':40B 'page':57B 'potenti':59B 'reus':42B 'run':64B 'runtim':24B 'text':7A,35B,73C 'use':3A,27B,67C 'use-after-fre':2A,26B,66C 'user':52B 'vulner':78C","nicknames":[],"mitigations":[],"who_affected":"Any installed Firefox build older than the fixed versions is affected, so any browser on a user's desktop or a managed fleet. Managed teams should push the update through their normal browser channel. Sites and servers you run are not exposed through this flaw.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:42+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117876","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117876","severity":null,"published_at":"2026-10-27T14:16:42+00:00","modified_at":"2026-10-27T14:16:42+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"}