{"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": "2026-07-21T18:56:01.149Z"}, "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"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-07-20T20:30:05.425Z"}}, {"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"}}]}}

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