CVE-2026-87078: Libnet idn encode perl · Net::IDN::Punycode versions from 2.302 before 2.590 for Perl leak the output
Affects libnet-idn-encode-perlSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical · fixed in 2.590 : patch libnet-idn-encode-perl as a priority.
Data as of 5 Nov 2026, 00:01 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 33% 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:H/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 4 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10libnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=bionicOther 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
A fixed version of Net::IDN::Punycode is available starting from version 2.590. Users should upgrade to version 2.590 or later to remediate this vulnerability. No other mitigation is indicated.
Description
Net::IDN::Punycode versions from 2.302 before 2.590 for Perl contain a vulnerability in the XS backend where the output buffer is leaked on every rejected label in decode_punycode. This occurs because the scalar buffer is allocated before input validation and only released on successful decoding, causing memory to be retained on failure. The flaw allows an attacker supplying invalid labels to grow the process memory by twice the label length per rejected call without needing a successful call.
References
- ubuntu.com/security/CVE-2026-87078 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-87078 (opens in a new tab)
- lists.security.metacpan.org/cve-announce/msg/43753020/ (opens in a new tab)
- github.com/robrwo/Net-IDN-Encode/commit/92572f726e48af5559de4cc8a831463b79dfb217.patch (opens in a new tab)
- github.com/robrwo/Net-IDN-Encode/commit/edad63e0eeeeb18d93bc6dfe4d9dcdff9c244e1b.patch (opens in a new tab)
- metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes (opens in a new tab)