{"id":"CVE-2026-113399","kind":"vulnerability","aliases":["CVE-2026-113399"],"related":[],"title":"Firefox and Thunderbird: SVG boundary check flaw fixed in 158.0.1","description":"Incorrect boundary conditions in the SVG component. This vulnerability was fixed in Firefox 158.0.1 and Thunderbird 158.0.1.","summary":"An incorrect boundary condition in Firefox and Thunderbird's SVG component was fixed in version 158.0.1. The sources do not say what an attacker can gain from it.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["desktop","firefox","other","thunderbird"],"not_affected_if":[],"how_to_check":"- Check the installed Firefox version with `firefox --version` or the About Firefox page.\n- Check the installed Thunderbird version with `thunderbird --version` or the About Thunderbird page.","fix":"- Update Firefox to `158.0.1` or later.\n- Update Thunderbird to `158.0.1` or later.","status":"open","published_at":"2026-10-20T13:16:40+00:00","first_seen_at":"2026-10-23T21:57:20+00:00","triaged_at":"2026-10-25T05:04:51+00:00","updated_at":"2026-10-25T05:04:51+00:00","category":"other","confidence":0.3,"triage":{"at":"2026-10-25T05:04:51Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `158.0.1` or later.\n- Update Thunderbird to `158.0.1` or later.","reach":"unknown","title":"Firefox and Thunderbird: SVG boundary check flaw fixed in 158.0.1","impact":"medium","summary":"An incorrect boundary condition in Firefox and Thunderbird's SVG component was fixed in version 158.0.1. The sources do not say what an attacker can gain from it.","category":"other","nicknames":[],"who_cares":["firefox","thunderbird","desktop"],"confidence":0.3,"needs_auth":"unknown","worst_case":"unknown; the sources do not describe the impact","analyst_note":"Find the Mozilla security advisory for the fix in Firefox 158.0.1 to learn the impact, trigger and any exploitation status.","how_to_check":"- Check the installed Firefox version with `firefox --version` or the About Firefox page.\n- Check the installed Thunderbird version with `thunderbird --version` or the About Thunderbird page.","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Teams that run Firefox or Thunderbird builds older than 158.0.1 on their machines are affected. The sources do not say whether the flaw needs a particular page, file or setting to be triggered, so unknown for who can skip it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000577,"input_tokens":3243,"output_tokens":506,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-113399':13A,16A '-2026':12A,15A '158.0.1':10A,36B,60C,63C 'attack':44B 'boundari':5A,23B,48C 'check':6A 'compon':31B,53C 'condit':24B,49C 'cve':11A,14A 'desktop':17B 'firefox':1A,18B,26B,59C 'fix':8A,33B,57C 'flaw':7A 'gain':46B 'incorrect':22B,47C 'say':41B 'sourc':38B 'svg':4A,30B,52C 'thunderbird':3A,20B,28B,62C 'version':35B 'vulner':55C","nicknames":[],"mitigations":[],"who_affected":"Teams that run Firefox or Thunderbird builds older than 158.0.1 on their machines are affected. The sources do not say whether the flaw needs a particular page, file or setting to be triggered, so unknown for who can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T13:16:40+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-113399","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-113399","severity":null,"published_at":"2026-10-20T13:16:40+00:00","modified_at":"2026-10-20T20:17:16+00:00","first_seen_at":"2026-10-23T21:57:20+00:00","fetched_at":"2026-10-23T22:28:58+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"}