MEDIUM CVSS 5.8
Published: 2026-01-28

CVE-2026-1539

gnome libsoup Security Advisory (CVE-2026-1539)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-1539 impacting gnome libsoup. Evaluated with CVSS Base Score of 5.8 (MEDIUM).

Original NVD Description

Source: NIST NVD
A flaw was found in the libsoup HTTP library that can cause proxy authentication credentials to be sent to unintended destinations. When handling HTTP redirects, libsoup removes the Authorization header but does not remove the Proxy-Authorization header if the request is redirected to a different host. As a result, sensitive proxy credentials may be leaked to third-party servers. Applications using libsoup for HTTP communication may unintentionally expose proxy authentication data.

📊 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 gnome / libsoup
Affected Versions -
Weakness Enumeration CWE-201

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-2026-1539 impacting gnome libsoup.

⚡ Nuclei Detection Template (YAML) cve-2026-1539.yaml
id: cve-2026-1539

info:
  name: gnome libsoup - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-1539 affecting gnome libsoup.
    Evaluation: A flaw was found in the libsoup HTTP library that can cause proxy authentication credentials to be sent to unintended destinations. When handling HTTP...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-1539
  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-2026-1539
    cwe-id: CWE-201
  tags: cve,cve-2026-1539,gnome,libsoup,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "libsoup"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-1539.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-1539
# Target: gnome libsoup | 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-2026-1539 (gnome libsoup)...")
    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 gnome libsoup 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-2026-1539.sh
# Recommended Remediation & Patching Commands for CVE-2026-1539
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install libsoup 2>/dev/null || \
sudo dnf upgrade libsoup 2>/dev/null || \
sudo yum update libsoup

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

# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-1539 in gnome libsoup?

Review vendor-specific security notices and update gnome libsoup 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-2026-1539?

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-2026-1539?

CVE-2026-1539 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-2026-1539
Weakness CWE-201
Vendor gnome
Product libsoup
Published 2026-01-28
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N