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No exploitation reportedFix availableAwaiting NVD analysis

CVE-2026-116270

MIME::Words versions before 5.521 for Perl allow memory exhaustion via repeated "=?" sequences in decode_mimewords

No exploitation reported by the sources we read.

  • Published2026-10-28
  • WeaknessCWE-407

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

MIME::Words versions before 5.521 for Perl allow memory exhaustion via repeated "=?" sequences in decode_mimewords. For each "=?" that does not start a complete encoded word, decode_mimewords appends an error message containing the whole input string to $@. A boundary of 8,000 "=?" pairs (16,000 bytes) adds 8,000 copies of itself to $@, about 128 MB. From version 5.518, MIME::Parser decodes every multipart boundary this way, so a remote sender can exhaust the memory of the parsing process with one Content-Type header.

Timeline

dates in UTC
  1. 2026-10-2817:33CVE publishedCNA

Versions per branch

Products declared by the CNA1 product

As CPANSec, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-10-28

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libmime-tools-perlUbuntu:26.10all versions · no fixed version listed
  • libmime-tools-perlUbuntu:26.04:LTSall versions · no fixed version listed
  • libmime-tools-perlUbuntu:24.04:LTSall versions · no fixed version listed
  • libmime-tools-perlUbuntu:22.04:LTSall versions · no fixed version listed
  • libmime-tools-perlUbuntu:20.04:LTSall versions · no fixed version listed
  • libmime-tools-perlUbuntu:18.04:LTSall versions · no fixed version listed
  • libmime-tools-perlUbuntu:16.04:LTSall versions · no fixed version listed
  • libmime-tools-perlUbuntu:14.04:LTSall versions · no fixed version listed

5 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-116270 Red Hat Product Security1 known affected

    perl-MIME-tools: perl-MIME-tools: Denial of Service via memory exhaustion from crafted MIME headers

    perl-MIME-tools.src as a component of Red Hat Enterprise Linux 6

Full record on NVD

Fix

  1. No fix available, says the vendor Red Hat Product Security CVE-2026-116270 · 1 productAffected

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-10-28
Last Modified
2026-11-05
NVD status
Awaiting Analysis
GitHub Advisory
GHSA-jq2x-c3x3-gv8c

Frequently asked questions

What is CVE-2026-116270?

MIME::Words versions before 5.521 for Perl allow memory exhaustion via repeated "=?" sequences in decode_mimewords. For each "=?" that does not start a complete encoded word, decode_mimewords appends an error message containing the whole input string to $@. A boundary of 8,000 "=?" pairs (16,000 bytes) adds 8,000 copies of itself to $@, about 128 MB. From version 5.518, MIME::Parser decodes every multipart boundary this way, so a remote sender can exhaust the memory of the parsing process with one Content-Type header.

Is CVE-2026-116270 actively exploited?

Active exploitation of CVE-2026-116270 has not been confirmed. Its EPSS score was 0.2% on 2026-11-05, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-116270?

CVE-2026-116270 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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