{"id":"UBUNTU-CVE-2026-87081","details":"Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii. to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.","modified":"2026-09-24T02:00:38.863756665Z","published":"2026-09-22T08:16:00Z","upstream":["CVE-2026-87081"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-87081"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-87081"},{"type":"REPORT","url":"https://lists.security.metacpan.org/cve-announce/msg/43753018/"},{"type":"REPORT","url":"https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch"},{"type":"REPORT","url":"https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch"},{"type":"REPORT","url":"https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"}],"affected":[{"package":{"name":"libnet-idn-encode-perl","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.202-1","2.300-1","2.300-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnet-idn-encode-perl","binary_version":"2.300-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-87081.json"}},{"package":{"name":"libnet-idn-encode-perl","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.400-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.400-1build1","binary_name":"libnet-idn-encode-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-87081.json"}},{"package":{"name":"libnet-idn-encode-perl","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.500-1","2.500-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.500-1build1","binary_name":"libnet-idn-encode-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-87081.json"}},{"package":{"name":"libnet-idn-encode-perl","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.500-1build2","2.500-2","2.500-2build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnet-idn-encode-perl","binary_version":"2.500-2build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-87081.json"}},{"package":{"name":"libnet-idn-encode-perl","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.500-3","2.500-3build1","2.500-3build2","2.500-5"],"ecosystem_specific":{"binaries":[{"binary_name":"libnet-idn-encode-perl","binary_version":"2.500-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-87081.json"}},{"package":{"name":"libnet-idn-encode-perl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.500-5build1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.500-5build1","binary_name":"libnet-idn-encode-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-87081.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"},{"type":"Ubuntu","score":"medium"}]}