LOW CVSS 3.7
Published: 2026-10-26

CVE-2026-19742

Software Component Security Advisory (CVE-2026-19742)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-19742 impacting Software Component. Evaluated with CVSS Base Score of 3.7 (LOW).

Original NVD Description

Source: NIST NVD
The IPv6 stack derived the long-lived secret key used to compute RFC 7217 stable interface identifiers (gen_stable_iid() in subsys/net/ip/ipv6.c) and RFC 8981 temporary interface identifiers (gen_temporary_iid() in subsys/net/ip/ipv6_pe.c) with sys_rand_get(). That API is documented as not cryptographically secure, while both RFCs require this key to be an unpredictable random value of at least 128 bits — the unpredictability of every generated IID rests entirely on it. Depending on the platform, sys_rand_get() resolves either to a hardware entropy device or, on boards whose entropy driver sets CONFIG_ENTROPY_NEEDS_PRNG, to the non-cryptographic xoshiro128++ generator in subsys/random/random_xoshiro128.c, which keeps a single global 128-bit state shared with every other sys_rand_get() consumer. Many of those consumers put their output directly on the wire (ephemeral source ports, DNS query IDs, CoAP message IDs and tokens, DHCPv6 transaction IDs, WebSocket masking keys), and the xoshiro state transition is invertible, so an observer of a device's traffic can recover the generator state and reconstruct the IID secret key. Additionally, with the entropy-device backend sys_rand_get() silently falls back to k_cycle_get_32() samples when the entropy driver fails, and returns no error, so the key could be derived from the cycle counter without the caller noticing. With the key known, stable IIDs become directly computable for any prefix (the remaining HMAC inputs — prefix, interface index, interface name, DAD counter — are guessable), and temporary IIDs become linkable after a cheap search over the mixed-in k_uptime_get_32() value. This defeats the properties both features exist to provide: an attacker can track a device across networks and prefixes, and can predict its address inside a /64 without scanning, removing the usual barrier to directly targeting the host. There is no memory-safety, integrity, or availability impact. The fix generates the key with sys_csrand_get() and aborts IID generation with -EIO when no cryptographic randomness is available, instead of silently deriving addresses from a predictable key. Both CONFIG_NET_IPV6_IID_STABLE and CONFIG_NET_IPV6_PE are experimental and disabled by default; builds using CONFIG_TEST_RANDOM_GENERATOR remain predictable by design, as sys_csrand_get() is deliberately routed back to the test generator there.

📊 CVSS v3.1 Metric Breakdown

🎯 Affected Versions Matrix

Affected Product Generic/Unknown / Software Component
Affected Versions Unspecified
Weakness Enumeration CWE-Not-Specified

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-2026-19742 impacting Software Component.

⚡ Nuclei Detection Template (YAML) cve-2026-19742.yaml
id: cve-2026-19742

info:
  name: Software Component - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: low
  description: |
    Automated signature & scanner for CVE-2026-19742 affecting Software Component.
    Evaluation: The IPv6 stack derived the long-lived secret key used to compute RFC 7217 stable interface identifiers (gen_stable_iid() in subsys/net/ip/ipv6.c) and ...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-19742
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 3.7
    cve-id: CVE-2026-19742
    cwe-id: CWE-Not-Specified
  tags: cve,cve-2026-19742,generic,software,low

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "Server"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-19742.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-19742
# Target: Software Component | CVSS: 3.7 (LOW)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-19742 (Software Component)...")
    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 Software Component scope (Unspecified).")
        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-2026-19742.sh
# Recommended Remediation & Patching Commands for CVE-2026-19742
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install software 2>/dev/null || \
sudo dnf upgrade software 2>/dev/null || \
sudo yum update software

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

# 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.
Technical Analysis
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-19742 in Software Component?

Review vendor-specific security notices and update Software Component 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-2026-19742?

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-2026-19742?

CVE-2026-19742 is classified with a CVSS 3.1 Base Score of 3.7 (LOW). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
3.7
LOW SEVERITY
CVE ID CVE-2026-19742
Weakness CWE-Not-Specified
Vendor Generic/Unknown
Product Software Component
Published 2026-10-26
Vector N/A