TI-2026-65750 Aliases CVE-2026-103680 GHSA-qr96-v34j-wcrq

Tnef: heap buffer overflow in find_free_number() via numbered-backup suffix generation

LOW 29CWE-787Published 2026-10-01 · Updated 2026-10-01

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00322 25th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	tnef	up to 1.4.18	—	No fix listed	CNA

tnef Vendor— Affected up to 1.4.18 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:tnef_project:tnef::::::::	up to 1.4.18	Vulnerable	Tnef Project

cpe:2.3:a:tnef_project:tnef:*:*:*:*:*:*:*:* Versions up to 1.4.18 Vulnerable ·Tnef Project

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product

Red Hat

Timeline

2026-10-02 Threatist record created from CVE-2026-103680
2026-10-03 Alias added: GHSA-qr96-v34j-wcrq
2026-10-05 CVSS score added · NVD

References

Advisory 2

Other 1

https://github.com/verdammelt/tnef

TI-2017-06404 An integer underflow has been identified in the unicode_to_utf8() function in tnef 1.4.14. CVSS 3.0CRITICAL 9.8
TI-2017-04142 An issue was discovered in tnef before 1.4.13. CVSS 3.0HIGH 7.8
TI-2017-04141 An issue was discovered in tnef before 1.4.13. CVSS 3.0HIGH 7.8
TI-2017-04140 An issue was discovered in tnef before 1.4.13. CVSS 3.0HIGH 7.8
TI-2017-04139 An issue was discovered in tnef before 1.4.13. CVSS 3.0HIGH 7.8
TI-2026-65748 Tnef: heap out-of-bounds read in get_rtf_data_from_buf() via uncompressed rtf mapi value CVSS 3.1HIGH 8.1

See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences