CVE-2026-15168: Wireshark Information Disclosure Flaw

CVE-2026-15168 Overview

CVE-2026-15168 is an information disclosure vulnerability in the Binary Logging Format (BLF) file parser used by Wireshark 4.6.0 through 4.6.6 and 4.4.0 through 4.4.16. The flaw stems from use of uninitialized memory ([CWE-457]) during BLF capture file processing. An attacker who convinces a local analyst to open a crafted BLF file can trigger the condition and potentially read small fragments of process memory. Exploitation requires local access and user interaction, and the scope of exposed data is limited to the Wireshark process context.

Critical Impact
Opening a malicious BLF capture file in a vulnerable Wireshark build may disclose fragments of uninitialized process memory to the analyst's session.

Affected Products

Wireshark 4.6.0 through 4.6.6
Wireshark 4.4.0 through 4.4.16
Environments processing untrusted BLF (Binary Logging Format) capture files

Discovery Timeline

2026-07-08 - CVE-2026-15168 published to NVD
2026-07-08 - Last updated in NVD database
2026 - Wireshark Security Advisory WNPA-SEC-2026-60 released

Technical Details for CVE-2026-15168

Vulnerability Analysis

The vulnerability affects the BLF (Binary Logging Format) dissector, a Wireshark component that parses Vector Informatik CAN bus and automotive protocol capture files. The parser reads a specially crafted BLF file and references memory that was never initialized before use, matching the pattern described by [CWE-457] Use of Uninitialized Variable. The disclosed data is limited to whatever residual bytes exist in the allocated buffer at the time of the read. An attacker cannot control the specific contents disclosed, but repeated file processing can leak varying fragments. The condition does not affect integrity or availability of the Wireshark process.

Root Cause

A code path inside the BLF parser allocates a structure or buffer and then reads one or more fields before all bytes have been populated by the parsing logic. When the crafted input causes the parser to skip initialization, subsequent handling of that field exposes stale memory content that gets rendered to the dissection output.

Attack Vector

Exploitation requires the target user to open a malicious BLF file in a vulnerable version of Wireshark or tshark. The attacker has no network access requirement and cannot exploit the flaw remotely without user interaction. High attack complexity reflects the limited attacker control over what uninitialized data is disclosed. See the Wireshark Security Advisory WNPA-SEC-2026-60 and GitLab Work Item #21361 for technical details.

Detection Methods for CVE-2026-15168

Indicators of Compromise

Delivery of unsolicited .blf capture files to analyst workstations via email or chat channels
Wireshark or tshark processes crashing or producing anomalous dissection output when opening BLF files
Vulnerable Wireshark versions (4.6.0-4.6.6, 4.4.0-4.4.16) present on analyst endpoints

Detection Strategies

Inventory installed Wireshark versions across engineering and SOC endpoints and flag builds within the affected ranges
Monitor file transfers of .blf extensions from untrusted sources into analyst environments
Alert on Wireshark or tshark executions that load BLF files originating outside approved capture repositories

Monitoring Recommendations

Log endpoint process execution of wireshark.exe, Wireshark, and tshark with command-line arguments referencing .blf files
Track software inventory telemetry to confirm patch adoption across the fleet
Correlate BLF file opens with subsequent unusual outbound network activity from analyst hosts

How to Mitigate CVE-2026-15168

Immediate Actions Required

Upgrade Wireshark to a fixed release above 4.6.6 in the 4.6.x branch or above 4.4.16 in the 4.4.x branch
Restrict BLF file handling to trusted sources until patching is complete
Communicate to analysts that unsolicited capture files should not be opened on production workstations

Patch Information

Apply the vendor fix referenced in Wireshark Security Advisory WNPA-SEC-2026-60. The tracking issue is documented in GitLab Work Item #21361. Package maintainers for Linux distributions typically backport Wireshark security fixes, so verify the installed package version reflects the corrected build.

Workarounds

Avoid opening BLF files from untrusted or unverified sources on vulnerable Wireshark installations
Perform capture file triage inside disposable virtual machines that contain no sensitive data
Where BLF parsing is not required, disable or remove the BLF file plugin from the Wireshark installation

bash

# Verify installed Wireshark version on Linux
wireshark --version | head -n 1
tshark --version | head -n 1

# Example: upgrade on Debian/Ubuntu after distribution patch is released
sudo apt-get update && sudo apt-get install --only-upgrade wireshark tshark