CRITICAL CVSS 9.8
Published: 2026-02-13

CVE-2026-26273

withknown known Security Advisory (CVE-2026-26273)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-26273 impacting withknown known. Evaluated with CVSS Base Score of 9.8 (CRITICAL).

Original NVD Description

Source: NIST NVD
Known is a social publishing platform. Prior to 1.6.3, a Critical Broken Authentication vulnerability exists in Known 1.6.2 and earlier. The application leaks the password reset token within a hidden HTML input field on the password reset page. This allows any unauthenticated attacker to retrieve the reset token for any user by simply querying the user's email, leading to full Account Takeover (ATO) without requiring access to the victim's email inbox. This vulnerability is fixed in 1.6.3.

📊 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 withknown / known
Affected Versions *
Weakness Enumeration CWE-200

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-2026-26273 impacting withknown known.

⚡ Nuclei Detection Template (YAML) cve-2026-26273.yaml
id: cve-2026-26273

info:
  name: withknown known - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-26273 affecting withknown known.
    Evaluation: Known is a social publishing platform. Prior to 1.6.3, a Critical Broken Authentication vulnerability exists in Known 1.6.2 and earlier. The applicati...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-26273
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-26273
    cwe-id: CWE-200
  tags: cve,cve-2026-26273,withknown,known,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "known"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-26273.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-26273
# Target: withknown known | 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-2026-26273 (withknown known)...")
    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 withknown known 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-2026-26273.sh
# Recommended Remediation & Patching Commands for CVE-2026-26273
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install known 2>/dev/null || \
sudo dnf upgrade known 2>/dev/null || \
sudo yum update known

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

# 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

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-26273 in withknown known?

Review vendor-specific security notices and update withknown known 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-2026-26273?

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-2026-26273?

CVE-2026-26273 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-2026-26273
Weakness CWE-200
Vendor withknown
Product known
Published 2026-02-13
Vector CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H