{"id":"CVE-2026-117961","kind":"vulnerability","aliases":["CVE-2026-117961"],"related":[],"title":"Firefox: incorrect boundary checks in text and font layout code","description":"Incorrect boundary conditions in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.","summary":"Firefox's Layout: Text and Fonts component has incorrect boundary conditions, a memory-safety class of bug. The sources do not say what an attacker gets beyond that, and the fix is in Firefox 159 and Firefox ESR 153.6.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser","desktop","firefox","runtime"],"not_affected_if":[],"how_to_check":"- `Help > About Firefox` and read the version; anything below `159` (or ESR below `153.6`) is exposed\n- unknown whether managed or enterprise builds carry a different version string","fix":"- Update Firefox to `159` or later\n- Update Firefox ESR to `153.6` or later","status":"open","published_at":"2026-10-27T14:16:52+00:00","first_seen_at":"2026-10-27T14:32:24+00:00","triaged_at":"2026-10-27T14:35:27+00:00","updated_at":"2026-10-27T14:35:27+00:00","category":"runtime","confidence":0.4,"triage":{"at":"2026-10-27T14:35:27Z","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: incorrect boundary checks in text and font layout code","impact":"medium","summary":"Firefox's Layout: Text and Fonts component has incorrect boundary conditions, a memory-safety class of bug. The sources do not say what an attacker gets beyond that, and the fix is in Firefox 159 and Firefox ESR 153.6.","category":"runtime","nicknames":[],"who_cares":["firefox","browser","desktop"],"confidence":0.4,"needs_auth":"no","worst_case":"unknown; the sources do not describe the impact","analyst_note":"Check the Mozilla security advisory for CVE-2026-117961 (from the NVD link) for the bug class, impact and whether it is exploitable from a web page.","how_to_check":"- `Help > About Firefox` and read the version; anything below `159` (or ESR below `153.6`) is exposed\n- unknown whether managed or enterprise builds carry a different version string","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions, since the flaw is in the browser's text and font rendering path and a page can reach it. The sources do not say whether any specific content or configuration is required, so unknown whether some installs can skip it.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000587,"input_tokens":3254,"output_tokens":524,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117961':13A,16A '-2026':12A,15A '153.6':60B,81C '159':56B,77C 'attack':46B 'beyond':48B 'boundari':3A,30B,62C 'browser':17B 'bug':38B 'check':4A 'class':36B 'code':10A 'compon':27B,70C 'condit':31B,63C 'cve':11A,14A 'desktop':18B 'esr':59B,80C 'firefox':1A,19B,21B,55B,58B,76C,79C 'fix':52B,74C 'font':8A,26B,69C 'get':47B 'incorrect':2A,29B,61C 'layout':9A,23B,66C 'memori':34B 'memory-safeti':33B 'runtim':20B 'safeti':35B 'say':43B 'sourc':40B 'text':6A,24B,67C 'vulner':72C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox or Firefox ESR older than the fixed versions, since the flaw is in the browser's text and font rendering path and a page can reach it. The sources do not say whether any specific content or configuration is required, so unknown whether some installs can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:52+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117961","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117961","severity":null,"published_at":"2026-10-27T14:16:52+00:00","modified_at":"2026-10-27T14:16:52+00:00","first_seen_at":"2026-10-27T14:32:24+00:00","fetched_at":"2026-10-27T14:32:24+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"}