{"id":"CVE-2026-123608","kind":"vulnerability","aliases":["CVE-2026-123608"],"related":[],"title":"Hickory DNS library: crafted messages exhaust CPU during name compression","description":"Hickory DNS hickory-proto from 0.3.1 before 0.26.1 contains a denial of service vulnerability in BinEncoder that allows remote attackers to exhaust CPU through quadratic-time name compression. Attackers can send malicious DNS messages with many records that add many candidate labels and trigger repeated linear scans during encoding, amplifying CPU exhaustion.","summary":"hickory-proto, the DNS protocol library in the Hickory DNS project, takes quadratic time when encoding messages that carry many records with many candidate labels. A remote attacker can send such DNS messages to exhaust a server's CPU and cause denial of service.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dns-server","hickory-dns","package","rust"],"not_affected_if":["client-only-use","version-0.26.1-or-later"],"how_to_check":"- Check the version of `hickory-proto` in your Cargo.lock (`cargo tree -i hickory-proto`)\n- Check whether your service uses hickory-proto to encode DNS responses (directly or via hickory-dns or hickory-resolver)","fix":"- `hickory-proto` `0.26.1` (fixed in releases from 0.3.1 up to, but not including, 0.26.1 are affected)","status":"open","published_at":"2026-11-08T02:16:55+00:00","first_seen_at":"2026-11-08T02:21:14+00:00","triaged_at":"2026-11-08T02:22:43+00:00","updated_at":"2026-11-08T02:22:43+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-08T02:22:43Z","model":"claude-haiku-5-5","output":{"fix":"- `hickory-proto` `0.26.1` (fixed in releases from 0.3.1 up to, but not including, 0.26.1 are affected)","reach":"internet","title":"Hickory DNS library: crafted messages exhaust CPU during name compression","impact":"medium","summary":"hickory-proto, the DNS protocol library in the Hickory DNS project, takes quadratic time when encoding messages that carry many records with many candidate labels. A remote attacker can send such DNS messages to exhaust a server's CPU and cause denial of service.","audience":"developers","category":"package","nicknames":[],"who_cares":["rust","hickory-dns","dns-server"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"remote attacker exhausts CPU and denies DNS service","analyst_note":"","how_to_check":"- Check the version of `hickory-proto` in your Cargo.lock (`cargo tree -i hickory-proto`)\n- Check whether your service uses hickory-proto to encode DNS responses (directly or via hickory-dns or hickory-resolver)","plain_action":"","needs_analyst":false,"not_affected_if":["client-only-use","version-0.26.1-or-later"],"who_is_affected":"Applications written in Rust that use hickory-proto from 0.3.1 before 0.26.1 to encode DNS messages, including DNS servers built on Hickory DNS, are exposed to remote CPU exhaustion. Services that only use DNS as a client or do not expose a DNS encoder to untrusted traffic can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000723,"input_tokens":4305,"output_tokens":584,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-123608':13A,16A '-2026':12A,15A '0.26.1':78C '0.3.1':76C 'add':110C 'allow':88C 'amplifi':121C 'attack':53B,90C,100C 'binencod':86C 'candid':49B,112C 'carri':44B 'caus':66B 'compress':10A,99C 'contain':79C 'cpu':7A,64B,93C,122C 'craft':4A 'cve':11A,14A 'denial':67B,81C 'dns':2A,18B,22B,29B,35B,57B,71C,104C 'dns-server':17B 'encod':41B,120C 'exhaust':6A,60B,92C,123C 'hickori':1A,21B,26B,34B,70C,73C 'hickory-dn':20B 'hickory-proto':25B,72C 'label':50B,113C 'librari':3A,31B 'linear':117C 'malici':103C 'mani':45B,48B,107C,111C 'messag':5A,42B,58B,105C 'name':9A,98C 'packag':23B 'project':36B 'proto':27B,74C 'protocol':30B 'quadrat':38B,96C 'quadratic-tim':95C 'record':46B,108C 'remot':52B,89C 'repeat':116C 'rust':24B 'scan':118C 'send':55B,102C 'server':19B,62B 'servic':69B,83C 'take':37B 'time':39B,97C 'trigger':115C 'vulner':84C","nicknames":[],"mitigations":[],"who_affected":"Applications written in Rust that use hickory-proto from 0.3.1 before 0.26.1 to encode DNS messages, including DNS servers built on Hickory DNS, are exposed to remote CPU exhaustion. Services that only use DNS as a client or do not expose a DNS encoder to untrusted traffic can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["dnsserver","hickorydns","high","package","rust"],"campaign_type":null,"search_a":"'-123608':13A,16A '-2026':12A,15A 'compress':10A 'cpu':7A 'craft':4A 'cve':11A,14A 'dns':2A 'exhaust':6A 'hickori':1A 'librari':3A 'messag':5A 'name':9A","search_b":"'attack':53B 'candid':49B 'carri':44B 'caus':66B 'cpu':64B 'denial':67B 'dns':18B,22B,29B,35B,57B 'dns-server':17B 'encod':41B 'exhaust':60B 'hickori':21B,26B,34B 'hickory-dn':20B 'hickory-proto':25B 'label':50B 'librari':31B 'mani':45B,48B 'messag':42B,58B 'packag':23B 'project':36B 'proto':27B 'protocol':30B 'quadrat':38B 'record':46B 'remot':52B 'rust':24B 'send':55B 'server':19B,62B 'servic':69B 'take':37B 'time':39B","search_c":"'0.26.1':78C '0.3.1':76C 'add':110C 'allow':88C 'amplifi':121C 'attack':90C,100C 'binencod':86C 'candid':112C 'compress':99C 'contain':79C 'cpu':93C,122C 'denial':81C 'dns':71C,104C 'encod':120C 'exhaust':92C,123C 'hickori':70C,73C 'hickory-proto':72C 'label':113C 'linear':117C 'malici':103C 'mani':107C,111C 'messag':105C 'name':98C 'proto':74C 'quadrat':96C 'quadratic-tim':95C 'record':108C 'remot':89C 'repeat':116C 'scan':118C 'send':102C 'servic':83C 'time':97C 'trigger':115C 'vulner':84C","first_public_at":"2026-05-01T14:00:55+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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-2026-123608","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123608","severity":null,"published_at":"2026-11-08T02:16:55+00:00","modified_at":"2026-11-08T02:16:55+00:00","first_seen_at":"2026-11-08T02:21:14+00:00","fetched_at":"2026-11-08T02:21:14+00:00","note":null}],"documents":[{"id":99367,"url":"https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-q2qq-hmj6-3wpp","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-05-01T14:00:55+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":99368,"url":"https://www.vulncheck.com/advisories/hickory-dns-hickory-proto-0.3.1-before-0.26.1-cpu-exhaustion-via-binencoder-name-compression","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}