{"id":"CVE-2026-123577","kind":"vulnerability","aliases":["CVE-2026-123577"],"related":[],"title":"Hickory DNS: unbounded DoH request bodies let remote attackers exhaust memory","description":"Hickory DNS from 0.24.0 before 0.26.2 contains a resource exhaustion vulnerability that allows remote attackers to consume server memory via unbounded DoH request bodies. Attackers can send large request bodies over HTTP/2 or HTTP/3 to a DNS over HTTP server, causing memory exhaustion and denial of service.","summary":"Hickory DNS, a Rust DNS server and library, does not limit the size of DNS-over-HTTPS request bodies. A remote attacker can send very large request bodies over HTTP/2 or HTTP/3 to exhaust server memory and cause a denial of service.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dns-over-https","hickory-dns","package","rust","self-hosted"],"not_affected_if":["no-doh-listener","udp-tcp-dns-only","version-0.26.2-or-later"],"how_to_check":"- Check the Hickory DNS version in your `Cargo.lock` or dependency tree (for example `cargo tree -p hickory-server`).\n- Confirm whether DNS-over-HTTPS (DoH) is enabled on your server.","fix":"- Hickory DNS: move to `0.26.2` or later.","status":"open","published_at":"2026-11-08T02:16:51+00:00","first_seen_at":"2026-11-08T02:21:12+00:00","triaged_at":"2026-11-08T02:22:52+00:00","updated_at":"2026-11-08T02:22:52+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-08T02:22:52Z","model":"claude-haiku-5-5","output":{"fix":"- Hickory DNS: move to `0.26.2` or later.","reach":"internet","title":"Hickory DNS: unbounded DoH request bodies let remote attackers exhaust memory","impact":"medium","summary":"Hickory DNS, a Rust DNS server and library, does not limit the size of DNS-over-HTTPS request bodies. A remote attacker can send very large request bodies over HTTP/2 or HTTP/3 to exhaust server memory and cause a denial of service.","audience":"businesses","category":"package","nicknames":[],"who_cares":["hickory-dns","rust","dns-over-https","self-hosted"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"remote attacker exhausts server memory, causing denial of service","analyst_note":"","how_to_check":"- Check the Hickory DNS version in your `Cargo.lock` or dependency tree (for example `cargo tree -p hickory-server`).\n- Confirm whether DNS-over-HTTPS (DoH) is enabled on your server.","plain_action":"","needs_analyst":false,"not_affected_if":["udp-tcp-dns-only","no-doh-listener","version-0.26.2-or-later"],"who_is_affected":"Only deployments of Hickory DNS from 0.24.0 before 0.26.2 that accept DNS-over-HTTPS queries over HTTP/2 or HTTP/3 are exposed. Servers that use only UDP or TCP DNS, or that sit behind a proxy which caps request body size, are less exposed.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000719,"input_tokens":4293,"output_tokens":580,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-123577':14A,17A '-2026':13A,16A '0.24.0':76C '0.26.2':78C 'allow':85C 'attack':9A,52B,87C,97C 'bodi':6A,49B,58B,96C,102C 'caus':68B,113C 'consum':89C 'contain':79C 'cve':12A,15A 'denial':70B,117C 'dns':2A,19B,24B,31B,34B,45B,74C,109C 'dns-over-http':18B,44B 'doh':4A,94C 'exhaust':10A,64B,82C,115C 'hickori':1A,23B,30B,73C 'hickory-dn':22B 'host':29B 'http':111C 'http/2':60B,104C 'http/3':62B,106C 'https':21B,47B 'larg':56B,100C 'let':7A 'librari':37B 'limit':40B 'memori':11A,66B,91C,114C 'packag':25B 'remot':8A,51B,86C 'request':5A,48B,57B,95C,101C 'resourc':81C 'rust':26B,33B 'self':28B 'self-host':27B 'send':54B,99C 'server':35B,65B,90C,112C 'servic':72B,119C 'size':42B 'unbound':3A,93C 'via':92C 'vulner':83C","nicknames":[],"mitigations":[],"who_affected":"Only deployments of Hickory DNS from 0.24.0 before 0.26.2 that accept DNS-over-HTTPS queries over HTTP/2 or HTTP/3 are exposed. Servers that use only UDP or TCP DNS, or that sit behind a proxy which caps request body size, are less exposed.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["dnsoverhttps","hickorydns","high","package","rust","selfhosted"],"campaign_type":null,"search_a":"'-123577':14A,17A '-2026':13A,16A 'attack':9A 'bodi':6A 'cve':12A,15A 'dns':2A 'doh':4A 'exhaust':10A 'hickori':1A 'let':7A 'memori':11A 'remot':8A 'request':5A 'unbound':3A","search_b":"'attack':52B 'bodi':49B,58B 'caus':68B 'denial':70B 'dns':19B,24B,31B,34B,45B 'dns-over-http':18B,44B 'exhaust':64B 'hickori':23B,30B 'hickory-dn':22B 'host':29B 'http/2':60B 'http/3':62B 'https':21B,47B 'larg':56B 'librari':37B 'limit':40B 'memori':66B 'packag':25B 'remot':51B 'request':48B,57B 'rust':26B,33B 'self':28B 'self-host':27B 'send':54B 'server':35B,65B 'servic':72B 'size':42B","search_c":"'0.24.0':76C '0.26.2':78C 'allow':85C 'attack':87C,97C 'bodi':96C,102C 'caus':113C 'consum':89C 'contain':79C 'denial':117C 'dns':74C,109C 'doh':94C 'exhaust':82C,115C 'hickori':73C 'http':111C 'http/2':104C 'http/3':106C 'larg':100C 'memori':91C,114C 'remot':86C 'request':95C,101C 'resourc':81C 'send':99C 'server':90C,112C 'servic':119C 'unbound':93C 'via':92C 'vulner':83C","first_public_at":"2026-09-03T21:50:46+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-2026-123577","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123577","severity":null,"published_at":"2026-11-08T02:16:51+00:00","modified_at":"2026-11-08T02:16:51+00:00","first_seen_at":"2026-11-08T02:21:12+00:00","fetched_at":"2026-11-08T02:21:12+00:00","note":null}],"documents":[{"id":99305,"url":"https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-5r56-v84h-c3w5","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-09-03T21:50:46+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":99306,"url":"https://www.vulncheck.com/advisories/hickory-dns-0.24.0-before-0.26.2-doh-unbounded-request-body-denial-of-service","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"}