{"id":"CVE-2026-116013","kind":"vulnerability","aliases":["CVE-2026-116013"],"related":[],"title":"OpenResty lua-resty-dns: malformed DNS replies crash name resolution","description":"OpenResty lua-resty-dns before 0.24 contains an improper input validation vulnerability in parse_section() and _decode_name() that fails to check resource record lengths against the received message. Attackers controlling or spoofing a queried nameserver can send truncated record headers or RDATA, raising uncaught Lua exceptions in resolver:query() that abort requests and break name resolution.","summary":"The lua-resty-dns library for OpenResty fails to check DNS record lengths, so a malformed reply from a queried nameserver raises an uncaught Lua exception. An attacker who controls or spoofs that nameserver can abort requests and break name resolution.","severity":"medium","cvss":6.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["lua-resty-dns","nginx","openresty","package"],"not_affected_if":["default-config"],"how_to_check":"- Check the installed lua-resty-dns version in your OpenResty or lua-resty packages, for example `opm list` or the lua-resty-dns source file's version header\n- Confirm whether your resolver code calls `resolver:query()` on untrusted or unreliable nameservers","fix":"- Upgrade lua-resty-dns to `0.24` or later\n- Reload OpenResty after the upgrade","status":"open","published_at":"2026-10-24T12:16:57+00:00","first_seen_at":"2026-10-24T12:47:58+00:00","triaged_at":"2026-10-25T04:00:01+00:00","updated_at":"2026-10-25T04:00:01+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T04:00:01Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade lua-resty-dns to `0.24` or later\n- Reload OpenResty after the upgrade","reach":"network","title":"OpenResty lua-resty-dns: malformed DNS replies crash name resolution","impact":"low","summary":"The lua-resty-dns library for OpenResty fails to check DNS record lengths, so a malformed reply from a queried nameserver raises an uncaught Lua exception. An attacker who controls or spoofs that nameserver can abort requests and break name resolution.","category":"package","nicknames":[],"who_cares":["openresty","lua-resty-dns","nginx"],"confidence":0.6,"needs_auth":"no","worst_case":"Name resolution fails and requests abort, causing a denial of service","analyst_note":"","how_to_check":"- Check the installed lua-resty-dns version in your OpenResty or lua-resty packages, for example `opm list` or the lua-resty-dns source file's version header\n- Confirm whether your resolver code calls `resolver:query()` on untrusted or unreliable nameservers","needs_analyst":false,"not_affected_if":["default-config"],"who_is_affected":"Services built on OpenResty that use lua-resty-dns to resolve names at request time are exposed. The risk depends on the resolver path: a spoofed or hostile nameserver is needed, so systems using trusted, internal resolvers face less exposure. Teams that do not run OpenResty or lua-resty-dns can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000608,"input_tokens":3346,"output_tokens":547,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-116013':14A,17A '-2026':13A,16A '0.24':73C 'abort':61B,119C 'attack':53B,97C 'break':64B,122C 'check':35B,89C 'contain':74C 'control':55B,98C 'crash':9A 'cve':12A,15A 'decod':84C 'dns':5A,7A,21B,29B,36B,71C 'except':51B,114C 'fail':33B,87C 'header':108C 'improp':76C 'input':77C 'length':38B,92C 'librari':30B 'lua':3A,19B,27B,50B,69C,113C 'lua-resty-dn':2A,18B,26B,68C 'malform':6A,41B 'messag':96C 'name':10A,65B,85C,123C 'nameserv':46B,59B,103C 'nginx':22B 'openresti':1A,23B,32B,67C 'packag':24B 'pars':81C 'queri':45B,102C,117C 'rais':47B,111C 'rdata':110C 'receiv':95C 'record':37B,91C,107C 'repli':8A,42B 'request':62B,120C 'resolut':11A,66B,124C 'resolv':116C 'resourc':90C 'resti':4A,20B,28B,70C 'section':82C 'send':105C 'spoof':57B,100C 'truncat':106C 'uncaught':49B,112C 'valid':78C 'vulner':79C","nicknames":[],"mitigations":[],"who_affected":"Services built on OpenResty that use lua-resty-dns to resolve names at request time are exposed. The risk depends on the resolver path: a spoofed or hostile nameserver is needed, so systems using trusted, internal resolvers face less exposure. Teams that do not run OpenResty or lua-resty-dns can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-24T12:16:57+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-116013","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-116013","severity":null,"published_at":"2026-10-24T12:16:57+00:00","modified_at":"2026-10-24T12:16:57+00:00","first_seen_at":"2026-10-24T12:47:58+00:00","fetched_at":"2026-10-24T12:47:58+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"}