{"id":"CVE-2026-87082","state":"PUBLISHED","title":"Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode","description":"Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode.\n\nNeither backend checks that its input is well-formed UTF-8, so a string with the UTF-8 flag set over malformed bytes, as the :utf8 PerlIO layer produces from any malformed input, reaches the encoder unchecked. On perl 5.32 and later the XS backend reports a malformed sequence with a length of `(STRLEN)-1`, so the scan steps back one byte instead of forward and never ends. On earlier perls the XS returns a valid label for a different name. The pure-Perl backend runs a regex over the flagged string. Depending on the bytes, it aborts with SIGBUS on perl 5.28 and later, dies with a panic, or returns a wrong label.\n\nThe documented conversion functions match the label against Unicode properties first and that match dies on such a string, so only a direct call to encode_punycode reaches the defect. The decoder is not affected.\n\nA direct caller encoding attacker-supplied bytes hangs, crashes or gets a label for a name the input never held.","publishedAt":"2026-09-22T07:25:37.650Z","updatedAt":"2026-09-22T17:07:32.600Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"CPANSec","products":["Net-IDN-Encode"],"affected":[{"packageName":"Net-IDN-Encode","packageURL":"pkg:cpan/Net-IDN-Encode","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.590","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","modules":["Net::IDN::Punycode"],"programFiles":["lib/Net/IDN/Punycode.xs","lib/Net/IDN/Punycode/PP.pm"],"programRoutines":[{"name":"Net::IDN::Punycode::encode_punycode"},{"name":"Net::IDN::Punycode::PP::encode_punycode"}],"repo":"https://github.com/robrwo/Net-IDN-Encode"}],"references":["https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes","https://github.com/robrwo/Net-IDN-Encode/commit/0918fb4a951ed5f4494c4cf202419c2842507ea4.patch","https://github.com/robrwo/Net-IDN-Encode/commit/59dc7f2c605a897bcbfe0ac5eb2b8dbe6792348d.patch","https://github.com/robrwo/Net-IDN-Encode/commit/accb6df57ad107ec0c4bfb27b21551eed97c700e.patch","https://github.com/robrwo/Net-IDN-Encode/commit/572af0183b3a6294e22c6b509268da09697cf77d.patch","http://www.openwall.com/lists/oss-security/2026/09/22/17"],"weaknesses":["CWE-835","CWE-1286"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/87xxx/CVE-2026-87082.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-87082","state":"PUBLISHED","datePublished":"2026-09-22T07:25:37.650Z","dateUpdated":"2026-09-22T17:07:32.600Z","assignerShortName":"CPANSec","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateReserved":"2026-09-08T19:22:20.005Z"},"containers":{"cna":{"title":"Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode","descriptions":[{"lang":"en","value":"Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode.\n\nNeither backend checks that its input is well-formed UTF-8, so a string with the UTF-8 flag set over malformed bytes, as the :utf8 PerlIO layer produces from any malformed input, reaches the encoder unchecked. On perl 5.32 and later the XS backend reports a malformed sequence with a length of `(STRLEN)-1`, so the scan steps back one byte instead of forward and never ends. On earlier perls the XS returns a valid label for a different name. The pure-Perl backend runs a regex over the flagged string. Depending on the bytes, it aborts with SIGBUS on perl 5.28 and later, dies with a panic, or returns a wrong label.\n\nThe documented conversion functions match the label against Unicode properties first and that match dies on such a string, so only a direct call to encode_punycode reaches the defect. The decoder is not affected.\n\nA direct caller encoding attacker-supplied bytes hangs, crashes or gets a label for a name the input never held."}],"affected":[{"packageName":"Net-IDN-Encode","packageURL":"pkg:cpan/Net-IDN-Encode","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.590","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","modules":["Net::IDN::Punycode"],"programFiles":["lib/Net/IDN/Punycode.xs","lib/Net/IDN/Punycode/PP.pm"],"programRoutines":[{"name":"Net::IDN::Punycode::encode_punycode"},{"name":"Net::IDN::Punycode::PP::encode_punycode"}],"repo":"https://github.com/robrwo/Net-IDN-Encode"}],"references":[{"url":"https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes","tags":["release-notes"]},{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/0918fb4a951ed5f4494c4cf202419c2842507ea4.patch","tags":["patch"]},{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/59dc7f2c605a897bcbfe0ac5eb2b8dbe6792348d.patch","tags":["patch"]},{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/accb6df57ad107ec0c4bfb27b21551eed97c700e.patch","tags":["patch"]},{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/572af0183b3a6294e22c6b509268da09697cf77d.patch","tags":["patch"]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-835","description":"CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1286","description":"CWE-1286 Improper Validation of Syntactic Correctness of Input","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"CPANSec","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateUpdated":"2026-09-22T07:25:37.650Z"},"solutions":[{"lang":"en","value":"Upgrade to Net-IDN-Encode 2.590-TRIAL or later."}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","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":"2026-09-22T15:07:50.514781Z","id":"CVE-2026-87082","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-22T15:07:54.683Z"}},{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/09/22/17"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-09-22T17:07:32.600Z"}}]}}}