CVE-2026-74766 Affecting libnet-idn-encode-perl package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-LIBNETIDNENCODEPERL-20044823
- published22 Sept 2026
- disclosed22 Sept 2026
Introduced: 22 Sep 2026
NewCVE-2026-74766 (opens in a new tab)How to fix?
There is no fixed version for Debian:unstable libnet-idn-encode-perl.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libnet-idn-encode-perl package and not the libnet-idn-encode-perl package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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.
The 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.
Version 2.301, the fix for CVE-2016-15059, introduced the defect. Only the XS backend is affected.
Decoding an attacker-supplied punycode label reads and writes freed heap memory.
References
- https://security-tracker.debian.org/tracker/CVE-2026-74766
- 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