{"id":"CVE-2026-40198","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-40198","generatedAt":"2026-10-28T03:25:41.352Z","title":"Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups.","description":"Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass.\n\n_pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like \"abcd\", \"1:2:3\", or \"1:2:3:4:5:6:7\" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17).\n\nThe packed values are used internally for mask and comparison operations. find() and bin_find() use Perl string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results. This can cause find() to incorrectly report an address as inside or outside a range.\n\nExample:\n\n  my $cidr = Net::CIDR::Lite->new(\"::/8\");\n  $cidr->find(\"1:2:3\");  # invalid input, incorrectly returns true\n\nThis is the same class of input validation issue as CVE-2021-47154 (IPv4 leading zeros) previously fixed in this module.\n\nSee also CVE-2026-40199, a related issue in the same function affecting IPv4 mapped IPv6 addresses.","published":"2026-04-10T22:16:21.000Z","lastModified":"2026-10-26T21:10:00.000Z","status":"Analyzed","sourceIdentifier":"9b29abf9-4ab0-4765-b253-1875cd9b441e","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"cwe":["CWE-1286"],"affected":["stigtsp/net\\"],"epss":{"score":0.00309,"percentile":0.23543,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/stigtsp/Net-CIDR-Lite/commit/25d65f85dbe4885959a10471725ec9d250a589c3.patch","tags":["Patch"],"source":"9b29abf9-4ab0-4765-b253-1875cd9b441e"},{"url":"https://metacpan.org/release/STIGTSP/Net-CIDR-Lite-0.23/changes","tags":["Release Notes"],"source":"9b29abf9-4ab0-4765-b253-1875cd9b441e"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-40199","tags":["Third Party Advisory"],"source":"9b29abf9-4ab0-4765-b253-1875cd9b441e"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-40198","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}