CVE-2026-5403 Overview
CVE-2026-5403 is a memory corruption vulnerability in the Subband Codec (SBC) dissector of Wireshark. The flaw affects Wireshark versions 4.6.0 through 4.6.4 and 4.4.0 through 4.4.14. Processing a malformed SBC-encoded capture file or live packet stream triggers a crash in the SBC codec component. The Wireshark Foundation classifies the issue under CWE-122 (Heap-based Buffer Overflow) and CWE-787 (Out-of-Bounds Write). Successful exploitation enables denial of service and potential code execution in the analyst's session.
Critical Impact
An attacker who convinces an analyst to open a crafted capture file or who injects malicious traffic onto a monitored network segment can crash Wireshark and potentially execute arbitrary code with the user's privileges.
Affected Products
- Wireshark 4.6.0 through 4.6.4
- Wireshark 4.4.0 through 4.4.14
- Systems running Wireshark or tshark for SBC traffic analysis
Discovery Timeline
- 2026-05-01 - CVE-2026-5403 published to NVD
- 2026-05-01 - Last updated in NVD database
Technical Details for CVE-2026-5403
Vulnerability Analysis
The vulnerability resides in the SBC codec dissector that Wireshark uses to decode Bluetooth audio payloads. The dissector mishandles bounds when processing SBC-encoded frames, producing a heap-based buffer overflow and an out-of-bounds write. Triggering the flaw requires user interaction: an analyst must open a crafted capture file, follow a malicious stream, or capture live traffic containing the malformed SBC frames.
The Common Weakness Enumeration entries [CWE-122] and [CWE-787] describe the underlying memory safety failure. The dissector writes attacker-controlled bytes outside the bounds of an allocated heap buffer. This corruption can crash the process or, with sufficient control over the overwritten memory, redirect execution. The EPSS percentile of 0.962 indicates relative scoring concentration despite a low absolute probability.
Root Cause
The root cause is improper validation of length and offset fields when decoding SBC frames inside the codec dissector. When the dissected frame describes more data than the allocated buffer can hold, the dissector writes past the heap allocation. See the Wireshark Security Advisory 2026-16 and GitLab Issue #21103 for the upstream technical analysis and patch.
Attack Vector
Exploitation is local and requires user interaction. An attacker delivers a malicious .pcap or .pcapng file to a target analyst through email, file share, or threat intelligence feed. When Wireshark or tshark parses the SBC frames, the corrupted dissector state crashes the process or executes attacker-supplied code in the user's context.
No verified public exploit code is available. Refer to the upstream advisory and issue tracker for technical details on the malformed frame structure.
Detection Methods for CVE-2026-5403
Indicators of Compromise
- Wireshark or tshark processes terminating unexpectedly while parsing capture files containing Bluetooth A2DP or SBC-encoded streams.
- Crash dumps referencing the SBC dissector or packet-sbc.c call frames.
- Receipt of unsolicited .pcap or .pcapng attachments containing SBC payloads from untrusted sources.
Detection Strategies
- Inventory endpoints running Wireshark 4.6.0–4.6.4 and 4.4.0–4.4.14 using software asset management or EDR telemetry.
- Hunt for child processes spawned by wireshark.exe or tshark that indicate post-crash code execution, such as shells or scripting engines.
- Alert on Wireshark process crashes correlated with capture files received via email gateways or external file transfers.
Monitoring Recommendations
- Monitor analyst workstations for abnormal Wireshark exit codes and Windows Error Reporting events tied to wireshark.exe.
- Log file provenance for .pcap and .pcapng artifacts opened on incident response systems.
- Forward crash telemetry from analyst hosts to a centralized SIEM for correlation with phishing and threat intelligence indicators.
How to Mitigate CVE-2026-5403
Immediate Actions Required
- Upgrade Wireshark to a fixed release identified in Wireshark Security Advisory 2026-16.
- Restrict opening of untrusted capture files to isolated analysis virtual machines without network or credential access.
- Communicate the advisory to incident response and network operations teams that routinely process third-party captures.
Patch Information
The Wireshark Foundation published the fix in Wireshark Security Advisory 2026-16. Apply the corresponding patched release from the 4.6.x or 4.4.x branch. Track upstream remediation status in GitLab Issue #21103.
Workarounds
- Disable the SBC dissector in Wireshark preferences under Analyze → Enabled Protocols until patches are applied.
- Avoid opening capture files from untrusted sources and decline to process unsolicited .pcap attachments.
- Run Wireshark under a least-privilege account and inside a sandboxed analysis environment to limit the impact of code execution.
# Disable SBC dissector via tshark preference override
tshark -o "sbc.enable:FALSE" -r suspicious_capture.pcapng
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
