CVE-2026-87081: Net-IDN-Encode (Perl module) · Inefficient Algorithmic Complexity
Affects Net-IDN-Encode (Perl module)Source CVE Database V5
Not known to be exploited · CVSS 7.5 High : upgrade to 2.590 soon.
Data as of 5 Nov 2026, 23:24 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.590
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade Net-IDN-Encode (Perl module) to 2.590.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
CPANNet-IDN-Encodepkg:cpan/Net-IDN-EncodeOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, avoid processing untrusted input that could trigger the quadratic complexity in punycode encoding.
Description
CVE-2026-87081 is a vulnerability in Net::IDN::UTS46 versions before 2.590 for Perl that allows CPU exhaustion via inefficient algorithmic complexity in punycode encoding. The flaw arises because the to_ascii function punycode encodes each label before applying the 63-byte DNS length limit, leading to quadratic time complexity when processing labels with many distinct non-ASCII characters. This can cause denial of service by exhausting CPU resources during encoding operations.
References
- metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes (opens in a new tab)
- github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch (opens in a new tab)
- github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch (opens in a new tab)
- openwall.com/lists/oss-security/2026/09/22/16 (opens in a new tab)