Reference page — cumulative record through Thursday, October 8, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-103680

CVE-2026-103680MEDIUM

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

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   R  U  N  N  H    6.5   .0033   23.7     —

AFFECTED
  Product  Versions     Fixed
  tnef     unspecified  —

TIMELINE
  Oct 1   Reserved by fedora
  Oct 1   Published (CNA: fedora)
  Oct 5   RESCORED — CVE-2026-103680 (tnef). CVSS 3.1 → 6.5 (NVD).

CWE-787 · CNA: fedora · CVSS v3.1 · 3 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
October 1, 2026	Reserved	Reserved by fedora
October 1, 2026	Published	Published (CNA: fedora)
October 5, 2026	RESCORED	RESCORED — CVE-2026-103680 (tnef). CVSS 3.1 → 6.5 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
—	tnef	—	—	—

Weaknesses

CWE-787

References (3)

https://access.redhat.com/security/cve/CVE-2026-103680 [Third Party Advisory]
https://bugzilla.redhat.com/show_bug.cgi?id=2544478 [Issue Tracking, Third Party Advisory]
https://github.com/verdammelt/tnef [Product]

Authoritative record: CVE-2026-103680 at cve.org

Weaknesses: CWE-787

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-103680 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Thursday, October 8, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.