A flaw was found in tnef. A remote attacker could exploit this vulnerability by providing a specially crafted Transport Neutral Encapsulation Format… (CVE-2026-103679)
Description
A vulnerability in tnef allows a remote attacker to cause a denial of service by providing a specially crafted TNEF file with multiple message bodies. This triggers improper memory management, resulting in use-after-free and double-free conditions that crash the application. The issue affects several specific versions of tnef. The CVSS score is 6.5, indicating a medium severity impact focused on availability.
CVSS v3.1
Score 6.5medium
Affected software
pkg:deb/ubuntu/tnef?arch=source&distro=xenialpkg:deb/ubuntu/tnef?arch=source&distro=bionicpkg:deb/ubuntu/tnef?arch=source&distro=focalpkg:deb/ubuntu/tnef?arch=source&distro=jammypkg:deb/ubuntu/tnef?arch=source&distro=noblepkg:deb/ubuntu/tnef?arch=source&distro=stonkingpkg:deb/ubuntu/tnef?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The tnef utility contains a flaw where processing a specially crafted Transport Neutral Encapsulation Format (TNEF) file with multiple message bodies leads to improper memory management. This causes use-after-free and double-free conditions during extraction, resulting in application crashes and denial of service. The vulnerability requires no privileges and can be triggered remotely by an attacker supplying a malicious TNEF file. The CVSS 3.1 score is 6.5 (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H), reflecting a network attack vector, low attack complexity, no privileges required, user interaction needed, unchanged scope, no confidentiality or integrity impact, and high impact on availability.
Potential Impact
Successful exploitation causes denial of service by crashing the affected application due to memory corruption. There is no impact on confidentiality or integrity. The attack requires user interaction to trigger the vulnerability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid processing untrusted TNEF files or ensure they come from trusted sources. Monitor vendor communications for updates on patches or official fixes.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-103679
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad3f4f62cdf04f6566575fa
Added to database: 10/17/2026, 22:21:42 UTC
Last enriched: 10/17/2026, 22:42:31 UTC
Last updated: 10/17/2026, 22:42:31 UTC
Views: 3
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