{"id":"CVE-2026-123575","kind":"vulnerability","aliases":["CVE-2026-123575"],"related":[],"title":"Hickory DNS: incomplete DoH requests exhaust server memory, causing denial of service","description":"Hickory DNS before 0.26.2 contains a resource exhaustion vulnerability in its DNS-over-HTTPS HTTP/2 server that lacks sufficient timeouts or limits for incomplete request bodies. Remote attackers can open DoH connections, send incomplete request bodies, and hold connections open to exhaust server memory.","summary":"Hickory DNS before 0.26.2 does not set enough timeouts or limits on incomplete request bodies in its DNS-over-HTTPS HTTP/2 server. A remote attacker can open many DoH connections and hold them open to exhaust server memory.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dns","hickory-dns","runtime","rust","self-hosted"],"not_affected_if":["doh-disabled","hickory-below-0.26.2-not-used"],"how_to_check":"- Check the installed Hickory DNS version (for example with `hickory-dns --version` or the version in your Cargo.lock) and see whether it is below `0.26.2`.\n- Check whether the DNS-over-HTTPS listener is enabled in your Hickory DNS configuration.","fix":"- Hickory DNS: move to `0.26.2` or later.","status":"open","published_at":"2026-11-08T02:16:50+00:00","first_seen_at":"2026-11-08T02:21:12+00:00","triaged_at":"2026-11-08T02:22:55+00:00","updated_at":"2026-11-08T02:22:55+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-08T02:22:55Z","model":"claude-haiku-5-5","output":{"fix":"- Hickory DNS: move to `0.26.2` or later.","reach":"internet","title":"Hickory DNS: incomplete DoH requests exhaust server memory, causing denial of service","impact":"low","summary":"Hickory DNS before 0.26.2 does not set enough timeouts or limits on incomplete request bodies in its DNS-over-HTTPS HTTP/2 server. A remote attacker can open many DoH connections and hold them open to exhaust server memory.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["hickory-dns","dns","self-hosted","rust"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"Server memory is exhausted, causing denial of service for DNS clients","analyst_note":"","how_to_check":"- Check the installed Hickory DNS version (for example with `hickory-dns --version` or the version in your Cargo.lock) and see whether it is below `0.26.2`.\n- Check whether the DNS-over-HTTPS listener is enabled in your Hickory DNS configuration.","plain_action":"","needs_analyst":false,"not_affected_if":["doh-disabled","hickory-below-0.26.2-not-used"],"who_is_affected":"Servers running Hickory DNS before 0.26.2 with the DNS-over-HTTPS HTTP/2 listener exposed to the network are affected. Deployments that do not serve DoH, or that sit behind a proxy that enforces request body timeouts, are less exposed. The sources do not say which configurations beyond this are affected.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000723,"input_tokens":4294,"output_tokens":587,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-123575':15A,18A '-2026':14A,17A '0.26.2':31B,70C 'attack':53B,95C 'bodi':42B,93C,103C 'caus':9A 'connect':58B,99C,106C 'contain':71C 'cve':13A,16A 'denial':10A 'dns':2A,19B,22B,29B,46B,68C,79C 'dns-over-http':45B,78C 'doh':4A,57B,98C 'enough':35B 'exhaust':6A,64B,74C,109C 'hickori':1A,21B,28B,67C 'hickory-dn':20B 'hold':60B,105C 'host':27B 'http/2':49B,82C 'https':48B,81C 'incomplet':3A,40B,91C,101C 'lack':85C 'limit':38B,89C 'mani':56B 'memori':8A,66B,111C 'open':55B,62B,97C,107C 'remot':52B,94C 'request':5A,41B,92C,102C 'resourc':73C 'runtim':23B 'rust':24B 'self':26B 'self-host':25B 'send':100C 'server':7A,50B,65B,83C,110C 'servic':12A 'set':34B 'suffici':86C 'timeout':36B,87C 'vulner':75C","nicknames":[],"mitigations":[],"who_affected":"Servers running Hickory DNS before 0.26.2 with the DNS-over-HTTPS HTTP/2 listener exposed to the network are affected. Deployments that do not serve DoH, or that sit behind a proxy that enforces request body timeouts, are less exposed. The sources do not say which configurations beyond this are affected.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["dns","hickorydns","high","runtime","rust","selfhosted"],"campaign_type":null,"search_a":"'-123575':15A,18A '-2026':14A,17A 'caus':9A 'cve':13A,16A 'denial':10A 'dns':2A 'doh':4A 'exhaust':6A 'hickori':1A 'incomplet':3A 'memori':8A 'request':5A 'server':7A 'servic':12A","search_b":"'0.26.2':31B 'attack':53B 'bodi':42B 'connect':58B 'dns':19B,22B,29B,46B 'dns-over-http':45B 'doh':57B 'enough':35B 'exhaust':64B 'hickori':21B,28B 'hickory-dn':20B 'hold':60B 'host':27B 'http/2':49B 'https':48B 'incomplet':40B 'limit':38B 'mani':56B 'memori':66B 'open':55B,62B 'remot':52B 'request':41B 'runtim':23B 'rust':24B 'self':26B 'self-host':25B 'server':50B,65B 'set':34B 'timeout':36B","search_c":"'0.26.2':70C 'attack':95C 'bodi':93C,103C 'connect':99C,106C 'contain':71C 'dns':68C,79C 'dns-over-http':78C 'doh':98C 'exhaust':74C,109C 'hickori':67C 'hold':105C 'http/2':82C 'https':81C 'incomplet':91C,101C 'lack':85C 'limit':89C 'memori':111C 'open':97C,107C 'remot':94C 'request':92C,102C 'resourc':73C 'send':100C 'server':83C,110C 'suffici':86C 'timeout':87C 'vulner':75C","first_public_at":"2026-09-03T22:01:35+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-2026-123575","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123575","severity":null,"published_at":"2026-11-08T02:16:50+00:00","modified_at":"2026-11-08T02:16:50+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":99301,"url":"https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-g5xf-qv55-wv37","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-09-03T22:01:35+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":99302,"url":"https://www.vulncheck.com/advisories/hickory-dns-before-0.26.2-doh-memory-exhaustion-via-incomplete-request-bodies","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"}