CVE-2026-87078

Publication date 22 September 2026

Last updated 4 November 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

9.1 · Critical

Score breakdown

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.

Status

Package Ubuntu Release Status
libnet-idn-encode-perl 26.10 stonking
Needs evaluation
26.04 LTS resolute
Vulnerable
24.04 LTS noble
Vulnerable
22.04 LTS jammy
Vulnerable
20.04 LTS focal
Vulnerable
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Not affected

Severity score breakdown

CVSS version: CVSS v3.0

Base score 9.1 · Critical

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

References

Other references

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