MEDIUM CVSS 4.7
Published: 2026-01-10

CVE-2026-21899

nasa cryptolib Security Advisory (CVE-2026-21899)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-21899 impacting nasa cryptolib. Evaluated with CVSS Base Score of 4.7 (MEDIUM).

Original NVD Description

Source: NIST NVD
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.

📊 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
High (PR:H)
Administrative credentials required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
Low (A:L)
Partial service performance degradation

🎯 Affected Versions Matrix

Affected Product nasa / cryptolib
Affected Versions *
Weakness Enumeration CWE-125

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-2026-21899 impacting nasa cryptolib.

⚡ Nuclei Detection Template (YAML) cve-2026-21899.yaml
id: cve-2026-21899

info:
  name: nasa cryptolib - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-21899 affecting nasa cryptolib.
    Evaluation: CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-21899
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
    cvss-score: 4.7
    cve-id: CVE-2026-21899
    cwe-id: CWE-125
  tags: cve,cve-2026-21899,nasa,cryptolib,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "cryptolib"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-21899.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-21899
# Target: nasa cryptolib | CVSS: 4.7 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-21899 (nasa cryptolib)...")
    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 nasa cryptolib 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-2026-21899.sh
# Recommended Remediation & Patching Commands for CVE-2026-21899
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install cryptolib 2>/dev/null || \
sudo dnf upgrade cryptolib 2>/dev/null || \
sudo yum update cryptolib

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

# 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
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Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-21899 in nasa cryptolib?

Review vendor-specific security notices and update nasa cryptolib 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-2026-21899?

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-2026-21899?

CVE-2026-21899 is classified with a CVSS 3.1 Base Score of 4.7 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
4.7
MEDIUM SEVERITY
CVE ID CVE-2026-21899
Weakness CWE-125
Vendor nasa
Product cryptolib
Published 2026-01-10
Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L