HIGH CVSS 8.0
Published: 2026-02-18

CVE-2026-27099

jenkins jenkins Security Advisory (CVE-2026-27099)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-27099?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-27099 impacting jenkins jenkins. Evaluated with CVSS Base Score of 8.0 (HIGH).

Original NVD Description

Source: NIST NVD
Jenkins 2.483 through 2.550 (both inclusive), LTS 2.492.1 through 2.541.1 (both inclusive) does not escape the user-provided description of the "Mark temporarily offline" offline cause, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Agent/Configure or Agent/Disconnect permission.

📊 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
Low (PR:L)
Standard user access required
User Interaction
Required (UI:R)
User must click or open resource
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 jenkins / jenkins
Affected Versions *
Weakness Enumeration CWE-79

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-2026-27099 impacting jenkins jenkins.

⚡ Nuclei Detection Template (YAML) cve-2026-27099.yaml
id: cve-2026-27099

info:
  name: jenkins jenkins - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-27099 affecting jenkins jenkins.
    Evaluation: Jenkins 2.483 through 2.550 (both inclusive), LTS 2.492.1 through 2.541.1 (both inclusive) does not escape the user-provided description of the "...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-27099
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
    cvss-score: 8.0
    cve-id: CVE-2026-27099
    cwe-id: CWE-79
  tags: cve,cve-2026-27099,jenkins,jenkins,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "jenkins"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-27099.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-27099
# Target: jenkins jenkins | CVSS: 8.0 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-27099 (jenkins jenkins)...")
    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 jenkins jenkins 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-2026-27099.sh
# Recommended Remediation & Patching Commands for CVE-2026-27099
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install jenkins 2>/dev/null || \
sudo dnf upgrade jenkins 2>/dev/null || \
sudo yum update jenkins

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

# 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-2026-27099 in jenkins jenkins?

Review vendor-specific security notices and update jenkins jenkins 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-2026-27099?

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-2026-27099?

CVE-2026-27099 is classified with a CVSS 3.1 Base Score of 8.0 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.0
HIGH SEVERITY
CVE ID CVE-2026-27099
Weakness CWE-79
Vendor jenkins
Product jenkins
Published 2026-02-18
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H