Cyber Resilience

CVE-2026-6521

DoS in Wireshark 4.4.0 – 4.4.14

Public PoCDoS
Published
30 April 2026
Modified
01 May 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS Score 0.0014 4th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-6521 is a medium-severity Infinite Loop (CWE-835) vulnerability in Wireshark Wireshark. Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

OpenFlow v5 protocol dissector infinite loops in Wireshark 4.6.0 to 4.6.4 and 4.4.0 to 4.4.14 allows denial of service

CWE(s)
CWE-835

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Why these techniques?

Infinite loop in Wireshark dissector directly enables application exploitation to crash/hang the process (endpoint DoS).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1499.004 Application or System Exploitation Impactconfidence: HIGH
Infinite loop in protocol dissector enables crafted packets to crash or hang Wireshark via application exploitation.
attack.mitre.org →
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-6531Same product: Wireshark Wireshark
CVE-2026-15163Same product: Wireshark Wireshark
CVE-2026-6528Same product: Wireshark Wireshark
CVE-2026-6534Same product: Wireshark Wireshark
CVE-2026-6522Same product: Wireshark Wireshark
CVE-2026-6536Same product: Wireshark Wireshark
CVE-2026-0960Same product: Wireshark Wireshark
CVE-2026-6523Same product: Wireshark Wireshark
CVE-2026-6519Same product: Wireshark Wireshark
CVE-2026-7375Same product: Wireshark Wireshark

Affected Assets

wireshark
wireshark
4.4.0 — 4.4.14 · 4.6.0 — 4.6.4

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-2 Flaw Remediation
Detect
Catch it (NIST detect / respond)
  • RA-5 Vulnerability Monitoring and Scanning
  • SI-4 System Monitoring
Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly requires timely patching of the Wireshark OpenFlow v5 dissector to eliminate the CWE-835 infinite loop.

RA-5 Vulnerability Monitoring and Scanning partial match
detect

Requires continuous vulnerability scanning that would identify the affected Wireshark 4.4.x/4.6.x versions before exploitation.

SI-4 System Monitoring partial match
detect

Enables monitoring of Wireshark processes for anomalous CPU or hang conditions indicative of the infinite-loop DoS.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (reviews, testing, static analysis) directly prevent introduction of infinite-loop defects.

ID.RA-01 partial match
prevents

Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing can uncover infinite-loop conditions before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates practices that can detect and prevent infinite-loop defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify loop-termination rules, indirectly reducing the weakness.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address loop termination and prevent infinite loops.

A.8.27 Secure system architecture and engineering principles none match
none

Secure architecture principles encourage designs that avoid unreachable exit conditions.

A.8.32 Change management none match
none

Change management can require review of loop logic when code is modified.

References