CVE-2026-116269: MIME::Field::ParamVal versions before 5.521 for Perl turn an RFC 2231 filename with a hyphenated language tag into an empty recommended filename
CVE-2026-116269 key facts
- CISA KEV
- Not listed (catalogue checked )
- Highest advisory rating
- Medium
- CVSS base score
- 5.3 (Red Hat)
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N· base score 5.3, scored by CISA-ADPAttack vector: network. Attack complexity: low. Privileges required: none. User interaction: none. Scope: unchanged. Confidentiality impact: none. Integrity impact: low. Availability impact: none.- Weakness
- CWE-436 Interpretation Conflict
- CISA SSVC
- Exploitation: none observed. Automatable: yes. Technical impact: partial. CISA, .
- Assigned by
- CPANSec (CNA)
- CVE record published
- Listed by VulniPulse
- Record changed
Ratings, versions and fixes are quoted from the vendor advisories that cover only CVE-2026-116269; each belongs to its advisory, not to every product listed. How records are collected and checked.
Description
MIME::Field::ParamVal versions before 5.521 for Perl turn an RFC 2231 filename with a hyphenated language tag into an empty recommended filename. A parameter such as filename*=utf-8'en-US'payload.exe is converted to an encoded word with the language tag appended to the charset. The decoder strips the language suffix only when it is a single word, so it cannot resolve the charset UTF-8*EN-US and returns an empty string. The recommended_filename() method returns that empty string rather than falling back to the name parameter. Other mail readers return payload.exe. A remote sender can get an attachment past a policy that checks file extensions on the recommended filename.
Text from the CVE.org record (CPANSec).
How do I fix CVE-2026-116269?
- Upgrade to MIME-tools 5.521 or later. (CVE.org record)
Vendor advisories for CVE-2026-116269
Proxmox
1 advisory- Advisory severityUnrated
Advisory [CVE-2026-116264 +9] Proxmox Mail Gateway: Several issues in libmime-tools-perl
PSA-2026-00091Source published
This bulletin covers 10 CVEs. The products, versions, score and guidance below describe the bulletin; check its source for applicability to this specific CVE.
The MIME::Tools package is used for parsing mails in Proxmox Mail Gateway. Recently two new releases for MIME::Tools were released upstream, fixing several issues, including 10, which were assigned CVE identifiers. The issues can result in bypassing certain mail-filter rules similar to issues PSA-2026-00005-1 and PSA-2026-00049-1. Additionally parsing certain messages could result in spending an excessive amount of CPU time by pmg-smtp-filter. PMG used the Max files setting of the Virus detector as general limit on the maximal number of parts in a mail since at least version 5.0. This effectively limited the effect of the unlimited CPU time. The fixes for the issues were backported and are available in version 5.515-1+pmg3 of libmime-tools-perl. Additionally a hard-coded limit on the…
- Affected products in this advisory
- Proxmox Mail Gateway
- Source-reported affected versions
- Affected-version details not available in this record.
- Source-reported fixed versions
- libmime-tools-perl 5.515-1+pmg3
- pmg-api 9.1.5
- Mitigation guidance
- Update to the fixed package versions: libmime-tools-perl >= 5.515-1+pmg3, pmg-api >= 9.1.5.
Red Hat
1 advisory- Advisory severityMedium5.3
Medium [CVE-2026-116269] Attachment filter bypass via improper filename decoding
CVE-2026-116269Source published Source updated
Attachment filter bypass via improper filename decoding. Red Hat rates this moderate (CVSS 5.3). Weakness: CWE-115. Affected products named by the advisory: Red Hat Enterprise Linux 6; Red Hat package: perl-mime-tools.
- Related products — impact not confirmed
- Red Hat Enterprise Linux 6
- Red Hat package: perl-mime-tools
- Source-reported affected versions
- < 5.521
- Source-reported fixed versions
- No fixed-version detail extracted. This does not mean no fix exists.
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
References
Timeline
- CVE record published
- First vendor advisory listed by VulniPulse
- CVE record last updated
More Proxmox advisories
PSA-2026-00090Nov 10, 2026Proxmox Mail Gateway: XSS in content-type display in quarantine viewsPSA-2026-00089Nov 10, 2026Proxmox: Several issues in libpve-http-server-perlPSA-2026-00065Oct 7, 2026Proxmox Mail Gateway: Bypass DMARC check by spoofed envelope sender headerPSA-2026-00064Oct 7, 2026Proxmox Mail Gateway: Administrator to root privilege escalationPSA-2026-00063Oct 7, 2026Proxmox Mail Gateway: Administrator to root privilege escalationPSA-2026-00099Nov 10, 2026Proxmox: Incomplete validation of UPID when handling "stop task" API requests
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