CVE-2021-4182 in Wireshark
Summary
by MITRE • 12/31/2021
Crash in the RFC 7468 dissector in Wireshark 3.6.0 and 3.4.0 to 3.4.10 allows denial of service via packet injection or crafted capture file
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Analysis
by VulDB Data Team • 11/04/2025
The vulnerability identified as CVE-2021-4182 represents a critical denial of service flaw within Wireshark's RFC 7468 dissector component. This issue affects multiple versions of the popular network protocol analyzer, specifically targeting versions 3.4.0 through 3.4.10 and the 3.6.0 release. The RFC 7468 dissector is responsible for parsing and analyzing data structures defined in the RFC 7468 standard, which governs the encoding of cryptographic messages using base64 encoding with PEM format. The flaw manifests when Wireshark processes malformed or specially crafted packets that trigger a crash in the dissector logic, rendering the application unstable and unresponsive.
The technical implementation of this vulnerability stems from inadequate input validation within the dissector module that handles RFC 7468 formatted data. When Wireshark encounters malformed data structures during packet analysis, the dissector fails to properly handle edge cases or invalid sequences, leading to memory corruption or stack overflow conditions. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read vulnerabilities. The flaw operates at the application layer of network analysis, specifically within the protocol decoding engine where raw packet data is transformed into human-readable protocol information for forensic analysis.
From an operational perspective, this vulnerability presents significant risks to network security professionals and analysts who rely on Wireshark for network troubleshooting and security monitoring. An attacker capable of injecting malicious packets into a network or crafting a specially formatted capture file can exploit this vulnerability to crash the Wireshark application, effectively denying service to legitimate users who require network analysis capabilities. This denial of service condition can be particularly devastating in security operations centers where network traffic analysis is critical for incident response and threat hunting activities. The attack vector is relatively simple to execute, requiring only the ability to influence network traffic or create capture files, making it accessible to adversaries with basic network knowledge.
The impact of CVE-2021-4182 extends beyond immediate service disruption to potentially compromise the integrity of network analysis workflows. When Wireshark crashes during packet analysis, any ongoing network monitoring activities cease, potentially missing critical security events or network anomalies that occurred during the crash window. This vulnerability also affects automated analysis systems that depend on Wireshark's stability for continuous network monitoring. Organizations using Wireshark for compliance monitoring, forensic analysis, or security research may experience significant operational disruption. The vulnerability's presence in multiple versions suggests that many deployments may be affected, requiring immediate patching across various Wireshark installations.
Mitigation strategies for this vulnerability primarily involve upgrading to patched versions of Wireshark where the RFC 7468 dissector has been corrected to properly handle malformed input data. Network administrators should prioritize patch management to ensure all Wireshark installations are updated to versions that address this specific vulnerability. Additionally, implementing network monitoring solutions that can detect and isolate malformed traffic before it reaches Wireshark analysis systems provides an additional layer of defense. Organizations may also consider implementing network segmentation or traffic filtering to prevent potentially malicious packets from reaching systems running Wireshark. The ATT&CK framework categorizes this vulnerability under T1499, which describes network disruption techniques, and T1566, which covers spearphishing with attachments, as the vulnerability can be exploited through crafted capture files. System administrators should also consider implementing process isolation for network analysis tools to limit the impact of potential crashes on overall system availability.