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No exploitation reportedFix available

CVE-2021-3403

No exploitation reported by the sources we read.

  • Published2021-03-04
  • WeaknessCWE-415 · CWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

In ytnef 1.9.3, the TNEFSubjectHandler function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potentially code execution) due to a double free which can be triggered via a crafted file.

Timeline

dates in UTC
  1. 2021-03-0422:15CVE publishedNVD

Versions per branch

NVD
Fedoraproject fedora
BranchAffectedFixed in
33.x= 33no fix published
Redhat enterprise linux
BranchAffectedFixed in
7.0= 7.0no fix published
Ytnef project ytnef
BranchAffectedFixed in
1.9= 1.9.3no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libytnefUbuntu:26.10all versions · no fixed version listed
  • libytnefUbuntu:26.04:LTSall versions · no fixed version listed
  • libytnefUbuntu:25.10all versions · no fixed version listed
  • libytnefUbuntu:24.04:LTSall versions · no fixed version listed
  • libytnefUbuntu:22.04:LTSall versions · no fixed version listed
  • libytnefUbuntu:20.04:LTSall versions · no fixed version listed
  • libytnefUbuntu:18.04:LTSall versions · no fixed version listed
  • libytnefUbuntu:16.04:LTSall versions · no fixed version listed

17 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-3403 Red Hat Product Security

    ytnef: double free in TNEFSubjectHandler function in lib/ytnef.c via crafted file

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.8read 2026-10-23
  • NVDCVSS 2.06.8read 2026-10-23
  • CNAweakness (CWE)CWE-416known since 2026-10-23
  • NVDweakness (CWE)CWE-415read 2026-10-23
  • FIRST EPSSEPSS score1.8 %2026-11-08
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2021-03-04
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-4pxg-g29h-qqfc

Frequently asked questions

What is CVE-2021-3403?

In ytnef 1.9.3, the TNEFSubjectHandler function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potentially code execution) due to a double free which can be triggered via a crafted file.

Is CVE-2021-3403 actively exploited?

Active exploitation of CVE-2021-3403 has not been confirmed. Its EPSS score was 1.8% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-3403?

CVE-2021-3403 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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