The pure-Perl decoder reads one digit at a time with four-argument substr and tests the result with defined to detect the end of the input. substr on an exhausted string returns the empty string rather than undef, so decoding continues past the end. The empty string converts to a digit value below the range, reducing the accumulator, and the decoder derives one extra code point and its position from it. The result is deterministic. The XS backend rejects the same label.
Net::IDN::Punycode uses this backend wherever the XS does not build.
The two backends disagree about what such a label means, so a sender can pick a label that one installation resolves to a name and another rejects.
Analysis and contextual insights are available on OpenCVE Cloud.
Vendor Solution
Upgrade to Net-IDN-Encode 2.590-TRIAL or later.
Tracking
Sign in to view the affected projects.
No advisories yet.
Tue, 22 Sep 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
ssvc
|
Tue, 22 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
|
Tue, 22 Sep 2026 07:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Net::IDN::Punycode::PP versions before 2.590 for Perl decode a truncated label to a name containing a character it never encoded in decode_punycode. The pure-Perl decoder reads one digit at a time with four-argument substr and tests the result with defined to detect the end of the input. substr on an exhausted string returns the empty string rather than undef, so decoding continues past the end. The empty string converts to a digit value below the range, reducing the accumulator, and the decoder derives one extra code point and its position from it. The result is deterministic. The XS backend rejects the same label. Net::IDN::Punycode uses this backend wherever the XS does not build. The two backends disagree about what such a label means, so a sender can pick a label that one installation resolves to a name and another rejects. | |
| Title | Net::IDN::Punycode::PP versions before 2.590 for Perl decode a truncated label to a name containing a character it never encoded in decode_punycode | |
| Weaknesses | CWE-1286 | |
| References |
|
Subscriptions
No data.
Status: PUBLISHED
Assigner: CPANSec
Published:
Updated: 2026-09-22T17:07:30.035Z
Reserved: 2026-09-08T19:22:20.005Z
Link: CVE-2026-87080
Updated: 2026-09-22T17:07:30.035Z
Status : Deferred
Published: 2026-09-22T08:16:40.750
Modified: 2026-09-22T19:07:00.983
Link: CVE-2026-87080
No data.
OpenCVE Enrichment
Updated: 2026-09-22T18:00:17Z
-
CWE-1286
Improper Validation of Syntactic Correctness of Input