Libmime tools perl: MIME::Field::ParamVal versions before 5.521 for Perl allow one invalid Content-Type parameter to
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::Field::ParamVal versions before 5.521 for Perl allow one invalid Content-Type parameter to hide the parameters after it, including the multipart boundary. Parameter parsing stops at the first parameter whose name it cannot read, such as x:y=1 or a name containing an 8-bit byte, and drops every parameter after it. When the boundary is among them, MIME::Parser keeps the multipart body as a single undecoded part without marking the parse as ambiguous. Mail readers that skip the invalid parameter still find the boundary. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.