{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64194","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","state":"PUBLISHED","assignerShortName":"CPANSec","dateReserved":"2026-07-19T10:13:00.756Z","datePublished":"2026-07-20T17:55:05.169Z","dateUpdated":"2026-08-30T20:06:49.756Z"},"containers":{"cna":{"affected":[{"collectionURL":"https://cpan.org/modules","defaultStatus":"unaffected","packageName":"Net-DNS","product":"Net::DNS","programFiles":["lib/Net/DNS/DomainName.pm"],"programRoutines":[{"name":"Net::DNS::DomainName::decode"}],"repo":"https://www.net-dns.org/svn/net-dns/","vendor":"NLNETLABS","versions":[{"lessThanOrEqual":"1.55","status":"affected","version":"0","versionType":"custom"}]}],"credits":[{"lang":"en","type":"reporter","value":"Steffen Ullrich"}],"descriptions":[{"lang":"en","value":"Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains.\n\nNet::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service.\n\nThe guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth.\n\nA crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data.\n\nThe vulnerability is triggered by `Net::DNS::Packet->new(\\$wire)` i.e. any point where the library decodes a DNS message from the network."}],"problemTypes":[{"descriptions":[{"cweId":"CWE-674","description":"CWE-674 Uncontrolled Recursion","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","shortName":"CPANSec","dateUpdated":"2026-07-20T17:55:05.169Z"},"references":[{"url":"https://www.net-dns.org/blog/#release-candidate-for-netdns-1.56"},{"tags":["issue-tracking"],"url":"https://rt.cpan.org/Ticket/Display.html?id=179946"},{"tags":["release-notes"],"url":"https://metacpan.org/release/NLNETLABS/Net-DNS-1.55_01/changes"}],"solutions":[{"lang":"en","value":"Upgrade to version 1.56 or later."}],"source":{"discovery":"UNKNOWN"},"timeline":[{"lang":"en","time":"2026-07-10T00:00:00.000Z","value":"Issue reported publicly via RT."},{"lang":"en","time":"2026-07-10T00:00:00.000Z","value":"Version 1.55_01 (release candidate for version 1.56) published on CPAN."},{"lang":"en","time":"2026-07-18T00:00:00.000Z","value":"Version 1.56 published on CPAN."}],"title":"Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains","x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/07/20/13"},{"url":"https://lists.debian.org/debian-lts-announce/2026/08/msg00052.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2026-08-30T20:06:49.756Z"}},{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-07-21T18:55:36.580996Z","id":"CVE-2026-64194","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-21T18:56:01.149Z"}}]}}