HIGH CVSS 8.2
Published: 2026-07-08

CVE-2026-29009

denx u-boot Security Advisory (CVE-2026-29009)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-29009 impacting denx u-boot. Evaluated with CVSS Base Score of 8.2 (HIGH).

Original NVD Description

Source: NIST NVD
U-Boot before 2026.07-rc2 contains a buffer overflow vulnerability in nfs_readlink_reply() (net/nfs-common.c) when CONFIG_CMD_NFS is enabled, allowing a malicious or compromised NFS server to overflow the 2048-byte nfs_path_buff buffer by returning multiple relative symlink targets that are appended without cumulative length validation. Attackers can send two or more READLINK responses containing relative symlink targets of approximately 1100 bytes each to corrupt adjacent BSS variables including nfs_server_ip, nfs_server_mount_port, nfs_server_port, nfs_our_port, nfs_state, and rpc_id, potentially achieving memory corruption and control over the NFS client state machine.

📊 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
None (C:N)
No data confidentiality impact
Integrity
Low (I:L)
Partial data modification possible
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product denx / u-boot
Affected Versions *
Weakness Enumeration CWE-120

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-2026-29009 impacting denx u-boot.

⚡ Nuclei Detection Template (YAML) cve-2026-29009.yaml
id: cve-2026-29009

info:
  name: denx u-boot - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-29009 affecting denx u-boot.
    Evaluation: U-Boot before 2026.07-rc2 contains a buffer overflow vulnerability in nfs_readlink_reply() (net/nfs-common.c) when CONFIG_CMD_NFS is enabled, allowing...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-29009
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
    cvss-score: 8.2
    cve-id: CVE-2026-29009
    cwe-id: CWE-120
  tags: cve,cve-2026-29009,denx,u-boot,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "u-boot"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-29009.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-29009
# Target: denx u-boot | CVSS: 8.2 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-29009 (denx u-boot)...")
    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 denx u-boot 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-2026-29009.sh
# Recommended Remediation & Patching Commands for CVE-2026-29009
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install u-boot 2>/dev/null || \
sudo dnf upgrade u-boot 2>/dev/null || \
sudo yum update u-boot

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

# 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-2026-29009 in denx u-boot?

Review vendor-specific security notices and update denx u-boot 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-2026-29009?

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-2026-29009?

CVE-2026-29009 is classified with a CVSS 3.1 Base Score of 8.2 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.2
HIGH SEVERITY
CVE ID CVE-2026-29009
Weakness CWE-120
Vendor denx
Product u-boot
Published 2026-07-08
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H