CVE-2026-103680: Out-of-bounds Write
A flaw was found in tnef. A heap-based buffer overflow can occur in the find_free_number() function when generating numbered backup suffixes for duplicate filenames. When numbered backups are enabled and file overwriting is disabled, an attacker can supply a specially crafted Transport Neutral Encapsulation Format (TNEF) file with an excessive number of colliding attachment filenames, causing the numeric counter to write past the allocated memory buffer. This issue may result in an application crash, leading to a Denial of Service (DoS), or potentially arbitrary code execution.
AI Analysis
Technical Summary
A heap-based buffer overflow exists in the find_free_number() function of tnef when handling duplicate attachment filenames with numbered backups enabled and file overwriting disabled. Excessive colliding filenames cause the numeric counter to write beyond allocated memory, potentially crashing the application or enabling code execution. This affects tnef versions >=0 and <=1.4.18. The issue is documented under CVE-2026-103680 with a low CVSS score of 3.1. The Red Hat advisory is available but does not explicitly state patch availability.
Potential Impact
The vulnerability can cause application crashes resulting in denial of service. There is also a potential for arbitrary code execution, though the CVSS vector indicates low impact with no confidentiality or integrity loss. No active exploitation is known.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory at https://access.redhat.com/security/cve/CVE-2026-103680 for current remediation guidance. Until a fix is applied, consider disabling numbered backups or avoiding processing untrusted TNEF files with many duplicate attachment names.
CVE-2026-103680: Out-of-bounds Write
Description
A flaw was found in tnef. A heap-based buffer overflow can occur in the find_free_number() function when generating numbered backup suffixes for duplicate filenames. When numbered backups are enabled and file overwriting is disabled, an attacker can supply a specially crafted Transport Neutral Encapsulation Format (TNEF) file with an excessive number of colliding attachment filenames, causing the numeric counter to write past the allocated memory buffer. This issue may result in an application crash, leading to a Denial of Service (DoS), or potentially arbitrary code execution.
CVSS v3.1
Score 3.1low
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
A heap-based buffer overflow exists in the find_free_number() function of tnef when handling duplicate attachment filenames with numbered backups enabled and file overwriting disabled. Excessive colliding filenames cause the numeric counter to write beyond allocated memory, potentially crashing the application or enabling code execution. This affects tnef versions >=0 and <=1.4.18. The issue is documented under CVE-2026-103680 with a low CVSS score of 3.1. The Red Hat advisory is available but does not explicitly state patch availability.
Potential Impact
The vulnerability can cause application crashes resulting in denial of service. There is also a potential for arbitrary code execution, though the CVSS vector indicates low impact with no confidentiality or integrity loss. No active exploitation is known.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory at https://access.redhat.com/security/cve/CVE-2026-103680 for current remediation guidance. Until a fix is applied, consider disabling numbered backups or avoiding processing untrusted TNEF files with many duplicate attachment names.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- fedora
- Date Reserved
- 2026-10-01T09:06:43.923Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-103680","vendor":"Red Hat"}]
Threat ID: 6abe7490a43b0b3b89bd1cc2
Added to database: 10/01/2026, 14:56:16 UTC
Last enriched: 10/01/2026, 15:20:44 UTC
Last updated: 10/02/2026, 03:04:13 UTC
Views: 10
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