{"id":"CVE-2026-87082","summary":"Net::IDN::Punycode versions before 2.590 for Perl hang, crash or return a wrong label via unvalidated malformed UTF-8 in encode_punycode","details":"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.","modified":"2026-09-24T03:46:57.122500245Z","published":"2026-09-22T07:25:37.650Z","database_specific":{"cwe_ids":["CWE-1286","CWE-835"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87082.json","cna_assigner":"CPANSec"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/09/22/17"},{"type":"WEB","url":"https://cpan.org/modules"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/87xxx/CVE-2026-87082.json"},{"type":"ADVISORY","url":"https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-87082"},{"type":"FIX","url":"https://github.com/robrwo/Net-IDN-Encode/commit/0918fb4a951ed5f4494c4cf202419c2842507ea4.patch"},{"type":"FIX","url":"https://github.com/robrwo/Net-IDN-Encode/commit/572af0183b3a6294e22c6b509268da09697cf77d.patch"},{"type":"FIX","url":"https://github.com/robrwo/Net-IDN-Encode/commit/59dc7f2c605a897bcbfe0ac5eb2b8dbe6792348d.patch"},{"type":"FIX","url":"https://github.com/robrwo/Net-IDN-Encode/commit/accb6df57ad107ec0c4bfb27b21551eed97c700e.patch"},{"type":"PACKAGE","url":"https://github.com/robrwo/Net-IDN-Encode"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/robrwo/net-idn-encode","events":[{"introduced":"0"},{"fixed":"6b903cf0aeb82ff60e98e180a26daf3f9943f167"},{"fixed":"0918fb4a951ed5f4494c4cf202419c2842507ea4"},{"fixed":"572af0183b3a6294e22c6b509268da09697cf77d"},{"fixed":"59dc7f2c605a897bcbfe0ac5eb2b8dbe6792348d"},{"fixed":"accb6df57ad107ec0c4bfb27b21551eed97c700e"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2.590"}],"source":["DESCRIPTION","REFERENCES"]}}],"versions":["v2.502","v2.501","Net-IDN-Encode-2.099_20131226","Net-IDN-Encode-2.099_20131225","Net-IDN-Encode-2.005","Net-IDN-Encode-2.003_2013881000","Net-IDN-Encode-2.003_2013880700","Net-IDN-Encode-2.003_2013122701","Net-IDN-Encode-2.003_2013122700","Net-IDN-Encode-2.003","Net-IDN-Encode-2.002","Net-IDN-Encode-2.001","Net-IDN-Encode-2.000_20120110","Net-IDN-Encode-2.000","Net-IDN-Encode-1.999_20120108","Net-IDN-Encode-1.999_20120107","Net-IDN-Encode-1.000","Net-IDN-Encode-0.999_20100110","Net-IDN-Encode-0.99_20091231","Net-IDN-Encode-0.99_20091216","Net-IDN-Encode-0.99_20080919","Net-IDN-Encode-0.99_20080914","Net-IDN-tools-0.99_20070912"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-87082.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}