Skip to main content

Ytnef CVE-2021-3403

HIGH
Use After Free (CWE-416)
2021-03-04 secalert@redhat.com
7.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.8 (HIGH). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A local attacker with access to the system could access freed memory to execute arbitrary code or crash the application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 1.8% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

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. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use smart pointers or garbage-collected languages. Set pointers to NULL after freeing. Enable memory sanitizers.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Use After Free (CWE-416), which allows attackers to access freed memory to execute arbitrary code or crash the application. 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. Affected products include: Ytnef Project Ytnef, Redhat Enterprise Linux, Fedoraproject Fedora.

Know when Ytnef gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 7.8 HIGH
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

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.

Threat Intelligence Overview

EPSS Score
1.8%
Top 25% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 1.8%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

61
Low Medium High Critical
KEV: 0
EPSS: +2
CVSS: +39
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)NVD

cpe:2.3:a:ytnef_project:ytnef:1.9.3:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

More in Ytnef

View all
CVE-2017-9146 HIGH POC
8.8 May 22

The TNEFFillMapi function in lib/ytnef.c in libytnef in ytnef through 1.9.2 does not ensure a nonzero count value before

CVE-2021-3404 HIGH POC
7.8 Mar 04

In ytnef 1.9.3, the SwapWord function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potential

CVE-2017-6800 HIGH POC
7.5 Mar 10

An issue was discovered in ytnef before 1.9.2. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitabl

CVE-2026-111146 MEDIUM POC
6.9 Oct 15

Heap out-of-bounds read in ytnef through 2.1.2 allows an attacker to crash the ytnefprint utility and incidentally leak

CVE-2026-111145 MEDIUM POC
6.9 Oct 15

Heap out-of-bounds read in ytnef through 2.1.2 allows unauthenticated local attackers to crash the application and leak

CVE-2017-9058 CRITICAL
9.8 May 18

In libytnef in ytnef through 1.9.2, there is a heap-based buffer over-read due to incorrect boundary checking in the SIZ

CVE-2017-9473 MEDIUM POC
5.5 Jun 07

In ytnef 1.9.2, the TNEFFillMapi function in lib/ytnef.c allows remote attackers to cause a denial of service (memory co

CVE-2017-9471 MEDIUM POC
5.5 Jun 07

In ytnef 1.9.2, the SwapWord function in lib/ytnef.c allows remote attackers to cause a denial of service (heap-based bu

CVE-2017-9470 MEDIUM POC
5.5 Jun 07

In ytnef 1.9.2, the MAPIPrint function in lib/ytnef.c allows remote attackers to cause a denial of service (NULL pointer

CVE-2017-9474 MEDIUM POC
5.5 Jun 07

In ytnef 1.9.2, the DecompressRTF function in lib/ytnef.c allows remote attackers to cause a denial of service (heap-bas

CVE-2017-9472 MEDIUM POC
5.5 Jun 07

In ytnef 1.9.2, the SwapDWord function in lib/ytnef.c allows remote attackers to cause a denial of service (heap-based b

CVE-2017-6306 HIGH
7.8 Feb 24

An issue was discovered in ytnef before 1.9.1. Rated high severity (CVSS 7.8), this vulnerability is no authentication r

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy