{"cve":"CVE-2026-74766","nvd":{"published":"2026-09-22T08:16:40.267","modified":"2026-09-22T19:07:00.983","status":"Deferred","description":"Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a decoded code point that reallocates the output buffer in decode_punycode.\n\nThe XS backend inserts each decoded code point into the string buffer of the scalar it returns. decode_punycode computes the insertion pointer first and only then grows the buffer when the code point does not fit. The growth reallocates the buffer and updates every pointer except the insertion pointer, so the move that follows and the write of the code point go through a freed pointer. The buffer starts at twice the label length, and a code point above U+FFFF takes four bytes in the output, so a label of such code points outgrows it and forces the reallocation.\n\nVersion 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected.\n\nDecoding an attacker-supplied punycode label reads and writes freed heap memory.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.4},"cwes":["CWE-416"],"references":["https://github.com/robrwo/Net-IDN-Encode/commit/259e74c5739175b063c5393a4ce4a0705678ba61.patch","https://github.com/robrwo/Net-IDN-Encode/commit/2fbc71e4d8517ab65c5d5d35fda086371b735a3f.patch","https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes","https://www.cve.org/CVERecord?id=CVE-2016-15059"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-74766","score":0.00141,"percentile":0.03434,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}