CVE-2026-103680: A flaw was found in tnef

Q: How do I fix CVE-2026-103680?

tnef: upgrade to newer than 1.4.18. Exact commands for each OS are on this page.

Q: Is CVE-2026-103680 being exploited?

CVE-2026-103680 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-103680 affect?

CVE-2026-103680 affects tnef. Severity is low (CVSS 3.1). 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 att

Q: How urgent is CVE-2026-103680?

Priority 17/100. No elevated risk signals yet.

Routine

LOW 3.1UPGRADE

CVE-2026-103680 is a low-severity flaw (CVSS 3.1) affecting tnef. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	3.1 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-787
Published	2026-10-01
Last modified	2026-10-05

Publisher (CNA): Fedora Project · Vendor: tnef project

Last updated 2026-10-05 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-01 12:17 UTCPublished CVE record published
2026-10-05 13:42 UTCUpdated Record last modified

tnef project tnef UPGRADE

Affected: <= 1.4.18

Fixed in: newer than 1.4.18

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tnef || rpm -q tnef || tnef --version

2. UPGRADE to newer than 1.4.18 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tnef

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tnef

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-103680?

tnef: upgrade to newer than 1.4.18. Exact commands for each OS are on this page.

Is CVE-2026-103680 being exploited?

CVE-2026-103680 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-103680 affect?

CVE-2026-103680 affects tnef. Severity is low (CVSS 3.1). 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 att

How urgent is CVE-2026-103680?

Priority 17/100. No elevated risk signals yet.

Related CVEs

CVE-2026-103678 MEDIUM 5.4 UPGRADE A flaw was found in tnef
CVE-2026-103679 MEDIUM 6.5 UPGRADE A flaw was found in tnef

References

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