CVE-2026-116266: Libmime tools perl · MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded
Affects libmime-tools-perlSource GCVE Database
Not known to be exploited.
Data as of 5 Nov 2026, 12:35 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 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 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10libmime-tools-perlpkg:deb/ubuntu/libmime-tools-perl?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlibmime-tools-perlpkg:deb/ubuntu/libmime-tools-perl?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlibmime-tools-perlpkg:deb/ubuntu/libmime-tools-perl?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlibmime-tools-perlpkg:deb/ubuntu/libmime-tools-perl?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSlibmime-tools-perlpkg:deb/ubuntu/libmime-tools-perl?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSlibmime-tools-perlpkg:deb/ubuntu/libmime-tools-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.
Description
MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded multipart boundary without flagging the parse as ambiguous. The multipart_boundary() method decodes RFC 2047 encoded words anywhere in the boundary, but the ambiguity check only fires when the whole value is one encoded word. A boundary such as abc=?us-ascii?Q?def?= is used as abcdef, and ambiguous_content() returns false. Encoded words are not allowed in parameters, so other mail readers split the message on the literal value. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.