CVE-2026-31869
Discourse is an open-source discussion platform.
Executive Summary
CVE-2026-31869 is a unknown severity vulnerability affecting pii-secrets, ai-code, appsec. It is classified as Information Exposure. Ensure your systems and dependencies are patched immediately to mitigate exposure risks.
Precogs AI Insight
"The primary vulnerability vector is rooted in within Discourse, allowing a lack of rigorous type checking mechanisms. If successfully exploited, a malicious user could execute arbitrary code on the target system, potentially leading to full system compromise. Precogs automatically detects reversible cryptographic functions and hardcoded secrets to harden the environment against lateral movement."
What is this vulnerability?
CVE-2026-31869 is categorized as a critical Code Injection / RCE flaw. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.
Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, the ComposerController#mentions endpoint reve...
This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.
Risk Assessment
| Metric | Value |
|---|---|
| CVSS Base Score | 0 (UNKNOWN) |
| Vector String | N/A |
| Published | March 20, 2026 |
| Last Modified | March 20, 2026 |
| Related CWEs | CWE-200, CWE-285, CWE-639 |
Impact on Systems
✅ Remote Code Execution: Attackers achieve arbitrary command execution within the context of the application server.
✅ Privilege Escalation: Initial code execution can be exploited to pivot and elevate privileges across the network.
✅ Persistent Backdoors: Attackers can bind reverse shells, modify source files, or inject persistent access mechanisms.
How to fix this issue?
Implement the following strategic mitigations immediately to eliminate the attack surface.
1. Remove Dynamic Evaluation Completely eliminate the use of dynamic evaluation functions (eval(), exec(), system()) on untrusted input.
2. Sandboxing If dynamic execution is an absolute business requirement, isolate the execution environment in tightly constrained, non-networked sandboxes (e.g., restricted WebAssembly or isolated containers).
3. Network Segmentation Restrict outbound traffic from the application server (egress filtering) to prevent reverse shell connections.
Vulnerability Signature
// Vulnerable Node.js Execution
const exec = require('child_process').exec;
const user_domain = req.query.domain;
// VULNERABLE: Injecting user input directly into system shell commands
exec('ping -c 4 ' + user_domain, (error, stdout, stderr) =\> \{
res.send(stdout);
\});
// EXPLOIT PAYLOAD: precogs.ai ; cat /etc/passwd
References and Sources
- NVD — CVE-2026-31869
- MITRE — CVE-2026-31869
- CWE-200 — MITRE CWE
- CWE-200 Details
- CWE-285 — MITRE CWE
- CWE-285 Details
- CWE-639 — MITRE CWE
- CWE-639 Details
- PII and Secrets Exposure
- AI Code Security Vulnerabilities
- Application Security Vulnerabilities
Vulnerability Code Signature
Attack Data Flow
| Stage | Detail |
|---|---|
| Source | Application error or debug endpoint |
| Vector | Verbose error messages or sensitive metadata returned to the client |
| Sink | HTTP response |
| Impact | Information gathering, aids in further attacks |
Vulnerable Code Pattern
# ❌ VULNERABLE: Information Exposure
@app.errorhandler(500)
def internal_error(error):
# Taint sink: returns stack trace to user
return f"Internal Server Error: {error}", 500
Secure Code Pattern
# ✅ SECURE: Generic error message
@app.errorhandler(500)
def internal_error(error):
# Log the detailed error internally
app.logger.error(f"Server Error: {error}")
# Return a generic message to the user
return "An internal server error occurred.", 500
How Precogs Detects This
Precogs API Security Engine comprehensively audits all web endpoints to ensure verbose error messages and sensitive metadata are not exposed.\n