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Fencer Intel
high 7.5

CVE-2026-116268 json

MIME::Field::ParamVal versions before 5.521 for Perl allow CPU exhaustion via unclosed comments in header parameters

published 12d ago modified 4d ago also EUVD-2026-112300

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

MIME::Field::ParamVal versions before 5.521 for Perl allow CPU exhaustion via unclosed comments in header parameters.

The comment pattern used to parse Content-Type and Content-Disposition parameters scans from each "(" to the next ")". In a field with no ")", every "(" scans to the end of the header and fails, so parsing takes time quadratic in the header length. The field is parsed again on each attribute lookup, several times per MIME entity.

A 40 KB header takes about 7 seconds to parse once.

Patch / fix

  • cpan MIME-tools 5.521
  • libmime-tools-perl Debian 14 5.522-1

debian advisories DEBIAN-CVE-2026-116268

  • perl-MIME-tools openSUSE Leap 16.0 5.522.0-bp160.1.1
  • perl-MIME-tools openSUSE Tumbleweed 5.522.0-1.1

opensuse advisories openSUSE-SU-2026:22226-1openSUSE-SU-2026:12347-1

Is CVE-2026-116268 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-116268 updated cvss 5.3

perl-MIME-tools: perl-MIME-tools: Denial of Service via unclosed comments in header parameters

  • Red Hat Enterprise Linux 6 perl-MIME-tools 5.427-4.el6
    affected: no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4d ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • cpan MIME-tools

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.