{"id":"CVE-2026-87078","published":"2026-09-22T08:16:40.530","lastModified":"2026-09-22T19:07:00.983","description":"Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode.\n\nThe XS backend allocates the scalar it returns before it validates the input, sizing the buffer at twice the input length. The scalar is released only on the success path, so each of the three croaks that reject a label leaves the scalar and its buffer allocated. Nothing bounds the label length in the to-Unicode direction, since the 63-byte DNS limit is checked only when converting to ASCII.\n\nOnly the XS backend is affected.\n\nA sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed.","cvssScore":9.1,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","cwes":["CWE-401"],"vendors":[],"products":[],"references":[{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch","tags":[]},{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch","tags":[]},{"url":"https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/09/22/13","tags":[]}],"exploitRefs":[{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch","tags":[]},{"url":"https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw in Net::IDN::Punycode allows attackers to cause a denial of service by sending invalid labels, leading to excessive memory allocation.","exploitability":"Exploitation is relatively easy as long as the attacker can send invalid labels to the application.","blast_radius":"If exploited, the impact is limited to the affected system, causing potential denial of service due to memory exhaustion.","remediation":"Upgrade to Net::IDN::Punycode version 2.590 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["dos","memory-leak","perl"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-28T09:05:33.570Z"}}