CVE-2026-6529 Overview
CVE-2026-6529 is a heap-based buffer overflow vulnerability affecting the iLBC audio codec dissector in Wireshark, a widely-used network protocol analyzer. When processing malformed iLBC audio data within captured network traffic, the application can crash, resulting in a denial of service condition. This vulnerability affects Wireshark versions 4.6.0 through 4.6.4 and 4.4.0 through 4.4.14.
Critical Impact
Attackers can crash Wireshark by crafting malicious capture files or injecting malformed iLBC audio packets into monitored network traffic, disrupting network analysis operations and potentially affecting incident response capabilities.
Affected Products
- Wireshark 4.6.0 to 4.6.4
- Wireshark 4.4.0 to 4.4.14
Discovery Timeline
- 2026-04-30 - CVE-2026-6529 published to NVD
- 2026-04-30 - Last updated in NVD database
Technical Details for CVE-2026-6529
Vulnerability Analysis
This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), a memory corruption issue that occurs when the iLBC audio codec dissector in Wireshark writes data beyond the allocated heap buffer boundaries. The iLBC (Internet Low Bitrate Codec) is commonly used for voice over IP applications, and Wireshark includes a dissector to analyze this codec's data within captured network packets.
When parsing specially crafted iLBC audio data, insufficient bounds checking allows the dissector to write past the end of a heap-allocated buffer. While this specific vulnerability results in a denial of service through application crash, heap-based buffer overflows can potentially be leveraged for more severe attacks in certain circumstances.
The vulnerability requires local access and user interaction, meaning an attacker must convince a user to open a malicious capture file or the victim must be monitoring a network where the attacker can inject malformed packets.
Root Cause
The root cause is improper validation of input data length within the iLBC codec dissector. When processing iLBC audio frames, the dissector fails to properly validate the size of incoming data against the allocated buffer size, leading to a heap-based buffer overflow condition (CWE-122). This allows malformed packets to trigger writes beyond the allocated memory region, corrupting heap memory and causing the application to crash.
Attack Vector
The attack vector for CVE-2026-6529 is local, requiring user interaction to exploit. An attacker can exploit this vulnerability through two primary methods:
- Malicious Capture File: The attacker creates a specially crafted pcap or pcapng file containing malformed iLBC audio data and convinces the victim to open it in Wireshark
- Network Injection: If the attacker has access to a network being monitored by Wireshark, they can inject malformed iLBC packets that trigger the vulnerability when the dissector processes them
The vulnerability manifests in the iLBC dissector's packet processing routines. When Wireshark encounters the malformed audio codec data, the heap-based buffer overflow occurs, leading to memory corruption and subsequent application crash. For detailed technical information, refer to the GitLab Wireshark Work Item and the Wireshark Security Advisory 2026-32.
Detection Methods for CVE-2026-6529
Indicators of Compromise
- Unexpected Wireshark application crashes when opening capture files or monitoring network traffic
- Core dumps or crash reports indicating memory corruption in iLBC dissector components
- Presence of unusually large or malformed iLBC audio frames in capture files
- Suspicious pcap/pcapng files from untrusted sources containing iLBC codec data
Detection Strategies
- Monitor Wireshark processes for unexpected termination or crash events
- Implement file integrity monitoring on capture file directories to detect suspicious files
- Use application crash monitoring tools to identify patterns of iLBC dissector failures
- Deploy endpoint detection solutions capable of identifying heap-based buffer overflow exploitation attempts
Monitoring Recommendations
- Enable crash reporting for Wireshark installations across the organization
- Monitor system logs for Wireshark process crashes, particularly those involving the iLBC dissector
- Track capture file sources and implement scanning for malformed packets before analysis
- Consider running Wireshark in isolated environments when analyzing untrusted capture files
How to Mitigate CVE-2026-6529
Immediate Actions Required
- Upgrade Wireshark to the latest patched version beyond 4.6.4 (for 4.6.x branch) or 4.4.14 (for 4.4.x branch)
- Avoid opening capture files from untrusted or unknown sources
- Disable the iLBC dissector if not required for your analysis workflows
- Run Wireshark in a sandboxed environment when analyzing potentially malicious captures
Patch Information
Wireshark has released security updates to address this vulnerability. Users should upgrade to the latest available version. For detailed patch information, refer to the Wireshark Security Advisory 2026-32 and the GitLab Wireshark Work Item for tracking the fix implementation.
Workarounds
- Disable the iLBC dissector via Wireshark preferences: Navigate to Analyze → Enabled Protocols and uncheck iLBC
- Use packet filtering to exclude iLBC traffic from analysis when full dissection is not required
- Process suspicious capture files in isolated virtual machines to contain potential crashes
- Implement network segmentation to limit exposure to malicious packet injection on monitored networks
# Disable iLBC dissector via command line
wireshark --disable-protocol iLBC
# Or configure in preferences file (~/.config/wireshark/disabled_protos)
echo "iLBC" >> ~/.config/wireshark/disabled_protos
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
