CPANSA-Net-IDN-Encode-2026-87078: Net-IDN-Encode vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-09-22T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-09-22T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 9.1 | Severity | Critical |
| Original language | Language | en | |
| Also referred to | |||
Vulnerability Description
Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode.
The 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.
Only the XS backend is affected.
A sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed.
Vulnerabilities
CVE-2026-87078
Vulnerability DescriptionNet::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output buffer on every rejected label in decode_punycode.
The 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.
Only the XS backend is affected.
A sender who supplies invalid labels grows the process by twice the label length per rejected call, with no successful call needed.
| Weakness | CWE-401 : Missing Release of Memory after Effective Lifetime |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Net-IDN-Encode greater than or equal 2.302 and less than 2.590 |
|
Fixed
- Net-IDN-Encode greater than or equal 2.590
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-Net-IDN-Encode-2026-87078 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-net-idn-encode-2026-87078.json - https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch external
https://github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch - https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch external
https://github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch - https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes external
https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes - http://www.openwall.com/lists/oss-security/2026/09/22/13 external
http://www.openwall.com/lists/oss-security/2026/09/22/13 - CVE-2026-87078 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2026-87078
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Tue Sep 22 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/