CVE-2026-96423
Description
A flaw was found in Wireshark. A heap-based buffer overflow in the X11 protocol dissector allows an attacker to cause a Denial of Service (DoS) by injecting malformed packets or providing a crafted capture file. Successful exploitation leads to an application crash, disrupting network packet inspection.
Mitigation
Disable the X11 protocol dissector if analyzing network traffic that does not require X11 packet decoding.
For command-line analysis using tshark, disable the protocol at runtime:
tshark --disable-protocol x11 -r <capture_file>
For persistent user configuration, add the protocol identifier to the disabled protocols file:
mkdir -p ~/.config/wireshark
echo "x11" >> ~/.config/wireshark/disabled_protos
In the Wireshark graphical interface, the dissector can be disabled by navigating to Analyze > Enabled Protocols, searching for "X11", unchecking the protocol entry, and clicking OK.
Caveats: Disabling this dissector prevents Wireshark from decoding and analyzing X11 protocol traffic. Running Wireshark sessions must be restarted for configuration file changes to take effect. Additionally, avoid opening capture files obtained from untrusted sources and avoid running packet capture utilities with elevated root privileges.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 7.1 | 5.5 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | Required | Required | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | High | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Frequently Asked Questions
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