CRITICAL CVSS 9.8
Published: 2026-04-06

CVE-2026-34841

usebruno bruno Security Advisory (CVE-2026-34841)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-34841 impacting usebruno bruno. Evaluated with CVSS Base Score of 9.8 (CRITICAL).

Original NVD Description

Source: NIST NVD
Bruno is an open source IDE for exploring and testing APIs. Prior to 3.2.1, Bruno was affected by a supply chain attack involving compromised versions of the axios npm package, which introduced a hidden dependency deploying a cross-platform Remote Access Trojan (RAT). Users of @usebruno/cli who ran npm install between 00:21 UTC and ~03:30 UTC on March 31, 2026 may have been impacted. Upgrade to 3.2.1

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product usebruno / bruno
Affected Versions *
Weakness Enumeration CWE-494

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-34841 impacting usebruno bruno.

⚡ Nuclei Detection Template (YAML) cve-2026-34841.yaml
id: cve-2026-34841

info:
  name: usebruno bruno - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-34841 affecting usebruno bruno.
    Evaluation: Bruno is an open source IDE for exploring and testing APIs. Prior to 3.2.1, Bruno was affected by a supply chain attack involving compromised versions...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-34841
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-34841
    cwe-id: CWE-494
  tags: cve,cve-2026-34841,usebruno,bruno,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "bruno"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-34841.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-34841
# Target: usebruno bruno | CVSS: 9.8 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-34841 (usebruno bruno)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against usebruno bruno scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-34841.sh
# Recommended Remediation & Patching Commands for CVE-2026-34841
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install bruno 2>/dev/null || \
sudo dnf upgrade bruno 2>/dev/null || \
sudo yum update bruno

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i bruno 2>/dev/null || rpm -qa | grep -i bruno

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-34841 in usebruno bruno?

Review vendor-specific security notices and update usebruno bruno packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-34841?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-34841?

CVE-2026-34841 is classified with a CVSS 3.1 Base Score of 9.8 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.8
CRITICAL SEVERITY
CVE ID CVE-2026-34841
Weakness CWE-494
Vendor usebruno
Product bruno
Published 2026-04-06
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H