MEDIUM CVSS 5.8
Published: 2026-01-12

CVE-2026-22772

linuxfoundation fulcio Security Advisory (CVE-2026-22772)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-22772 impacting linuxfoundation fulcio. Evaluated with CVSS Base Score of 5.8 (MEDIUM).

Original NVD Description

Source: NIST NVD
Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF. This vulnerability is fixed in 1.8.5.

📊 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
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
Low (C:L)
Partial information leakage
Integrity
None (I:N)
No system modification impact
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product linuxfoundation / fulcio
Affected Versions *
Weakness Enumeration CWE-918

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-2026-22772 impacting linuxfoundation fulcio.

⚡ Nuclei Detection Template (YAML) cve-2026-22772.yaml
id: cve-2026-22772

info:
  name: linuxfoundation fulcio - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-22772 affecting linuxfoundation fulcio.
    Evaluation: Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio's metaRegex...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-22772
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
    cvss-score: 5.8
    cve-id: CVE-2026-22772
    cwe-id: CWE-918
  tags: cve,cve-2026-22772,linuxfoundation,fulcio,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "fulcio"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-22772.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-22772
# Target: linuxfoundation fulcio | CVSS: 5.8 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-22772 (linuxfoundation fulcio)...")
    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 linuxfoundation fulcio 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-2026-22772.sh
# Recommended Remediation & Patching Commands for CVE-2026-22772
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install fulcio 2>/dev/null || \
sudo dnf upgrade fulcio 2>/dev/null || \
sudo yum update fulcio

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

# 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.

🔗 Verified Technical References

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-22772 in linuxfoundation fulcio?

Review vendor-specific security notices and update linuxfoundation fulcio 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-2026-22772?

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-2026-22772?

CVE-2026-22772 is classified with a CVSS 3.1 Base Score of 5.8 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.8
MEDIUM SEVERITY
CVE ID CVE-2026-22772
Weakness CWE-918
Vendor linuxfoundation
Product fulcio
Published 2026-01-12
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N