MEDIUM CVSS 6.8
Published: 2025-07-02

CVE-2025-52559

zulip zulip_server Security Advisory (CVE-2025-52559)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2025-52559 impacting zulip zulip_server. Evaluated with CVSS Base Score of 6.8 (MEDIUM).

Original NVD Description

Source: NIST NVD
Zulip is an open-source team chat application. From versions 2.0.0-rc1 to before 10.4 in Zulip Server, the /digest/ URL of a server shows a preview of what the email weekly digest would contain. This URL, though not the digest itself, contains a cross-site scripting (XSS) vulnerability in both topic names and channel names. This issue has been fixed in Zulip Server 10.4. A workaround for this issue involves denying access to /digest/.

📊 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
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
High (C:H)
Total information disclosure
Integrity
None (I:N)
No system modification impact
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product zulip / zulip_server
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-2025-52559 impacting zulip zulip_server.

⚡ Nuclei Detection Template (YAML) cve-2025-52559.yaml
id: cve-2025-52559

info:
  name: zulip zulip_server - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2025-52559 affecting zulip zulip_server.
    Evaluation: Zulip is an open-source team chat application. From versions 2.0.0-rc1 to before 10.4 in Zulip Server, the /digest/ URL of a server shows a preview of...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2025-52559
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N
    cvss-score: 6.8
    cve-id: CVE-2025-52559
    cwe-id: CWE-79
  tags: cve,cve-2025-52559,zulip,zulip_server,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "zulip_server"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2025-52559.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2025-52559
# Target: zulip zulip_server | CVSS: 6.8 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2025-52559 (zulip zulip_server)...")
    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 zulip zulip_server 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-2025-52559.sh
# Recommended Remediation & Patching Commands for CVE-2025-52559
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install zulip_server 2>/dev/null || \
sudo dnf upgrade zulip_server 2>/dev/null || \
sudo yum update zulip_server

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

# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2025-52559 in zulip zulip_server?

Review vendor-specific security notices and update zulip zulip_server 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-2025-52559?

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-2025-52559?

CVE-2025-52559 is classified with a CVSS 3.1 Base Score of 6.8 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.8
MEDIUM SEVERITY
CVE ID CVE-2025-52559
Weakness CWE-79
Vendor zulip
Product zulip_server
Published 2025-07-02
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N