CVE-2026-43892: AntSword jQuery Terminal RCE Vulnerability

CVE-2026-43892 Overview

CVE-2026-43892 affects AntSword, a cross-platform website management toolkit used by penetration testers and administrators. Versions prior to 2.1.16 contain an incomplete noxss() sanitization routine that fails to block format code injection through the jquery.terminal component. Attackers can exploit this flaw to achieve 1-click remote code execution against AntSword users. The vulnerability is classified under CWE-79 (Cross-Site Scripting). AntSword version 2.1.16 contains the fix.

Critical Impact

A single user interaction with attacker-controlled content allows remote code execution within the AntSword client, granting attackers full control over the operator's workstation.

Affected Products

• AntSword versions prior to 2.1.16
• AntSword cross-platform desktop client (Electron-based)
• Deployments relying on jquery.terminal output rendering

Discovery Timeline

• 2026-05-12 - CVE-2026-43892 published to NVD
• 2026-05-13 - Last updated in NVD database

Technical Details for CVE-2026-43892

Vulnerability Analysis

AntSword renders server responses inside a terminal-style interface powered by jquery.terminal. The noxss() function attempts to neutralize hostile HTML before it reaches the renderer. The sanitizer fails to account for jquery.terminal format codes, which use bracketed syntax to embed styled or interactive content. An attacker controlling a target server (or a server impersonated through a malicious redirect) can return crafted output containing format directives that the sanitizer passes through unchanged. When the AntSword operator clicks the rendered element, the embedded payload executes inside the Electron renderer context.

Because AntSword runs on Electron with privileged Node.js integration, script execution in the renderer translates directly into operating system command execution on the operator's host.

Root Cause

The root cause is incomplete input sanitization in the noxss() helper. The function blocks standard XSS vectors such as <script> tags and event handlers but does not strip jquery.terminal format codes, which can carry JavaScript handlers attached to terminal links. This is a classic sanitizer bypass where the allow-list of dangerous patterns does not cover all execution sinks reachable from the rendering library.

Attack Vector

Exploitation requires that an AntSword user connect to a malicious or compromised webshell endpoint. The endpoint returns crafted output containing jquery.terminal format codes with embedded JavaScript. The user must perform one interaction, typically a click, on the rendered element. Upon interaction, the payload executes with the privileges of the AntSword process, leading to arbitrary command execution on the operator's machine. The attack is network-reachable, requires no authentication on the attacker side, and depends on a single user click.

No verified public exploit code is available. See the GitHub Security Advisory for upstream technical details.

Detection Methods for CVE-2026-43892

Indicators of Compromise

• Outbound HTTP responses to AntSword clients containing jquery.terminal format sequences such as [[ followed by handler attributes
• Unexpected child processes spawned by the AntSword Electron binary, particularly shells (cmd.exe, powershell.exe, /bin/sh, bash)
• AntSword client connections to previously unseen or low-reputation webshell endpoints

Detection Strategies

• Inspect proxy and web gateway logs for AntSword user-agent traffic returning oversized or format-code-laden response bodies
• Hunt for process lineage where the AntSword executable parents interpreter or scripting processes
• Monitor endpoints running AntSword versions earlier than 2.1.16 through software inventory tooling

Monitoring Recommendations

• Alert on file writes or persistence changes originating from the AntSword process tree
• Capture and review network metadata for AntSword sessions to detect connections outside sanctioned engagement scopes
• Track installed AntSword versions across operator workstations and flag anything below 2.1.16

How to Mitigate CVE-2026-43892

Immediate Actions Required

• Upgrade all AntSword installations to version 2.1.16 or later without delay
• Restrict AntSword usage to isolated virtual machines or dedicated assessment workstations
• Audit recent AntSword session history for connections to untrusted endpoints during the exposure window

Patch Information

The maintainers fixed the issue in AntSword 2.1.16 by extending noxss() to neutralize jquery.terminal format codes before rendering. Refer to the GitHub Security Advisory GHSA-c63g-p4cp-r45x for the patch commit and full vendor guidance.

Workarounds

• Avoid connecting AntSword to webshells on systems not fully under your control until the upgrade is applied
• Run AntSword inside a disposable sandbox or container with no access to credentials or production networks
• Block outbound network access from operator workstations except to known engagement targets

# Verify installed AntSword version and upgrade
cd /path/to/antSword
git fetch --tags
git checkout v2.1.16
npm install