HIGH CVSS 8.8
Published: 2025-10-16

CVE-2025-62495

quickjs_project quickjs Security Advisory (CVE-2025-62495)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2025-62495?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2025-62495 impacting quickjs_project quickjs. Evaluated with CVSS Base Score of 8.8 (HIGH).

Original NVD Description

Source: NIST NVD
An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due to an inconsistent representation of the bytecode buffer size. * The regular expression bytecode is stored in a DynBuf structure, which correctly uses a $\text{size}\_\text{t}$ (an unsigned type, typically 64-bit) for its size member. * However, several functions, such as re_emit_op_u32 and other internal parsing routines, incorrectly cast or store this DynBuf $\text{size}\_\text{t}$ value into a signed int (typically 32-bit). * When a large or complex regular expression (such as those generated by a recursive pattern in a Proof-of-Concept) causes the bytecode size to exceed $2^{31}$ bytes (the maximum positive value for a signed 32-bit integer), the size value wraps around, resulting in a negative integer when stored in the int variable (Integer Overflow). * This negative value is subsequently used in offset calculations. For example, within functions like re_parse_disjunction, the negative size is used to compute an offset (pos) for patching a jump instruction. * This negative offset is then incorrectly added to the buffer pointer (s->byte\_code.buf + pos), leading to an out-of-bounds write on the first line of the snippet below: put_u32(s->byte_code.buf + pos, len);

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Adjacent (AV:A)
Requires shared subnet / local network access
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
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 quickjs_project / quickjs
Affected Versions *
Weakness Enumeration CWE-191

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-2025-62495 impacting quickjs_project quickjs.

⚡ Nuclei Detection Template (YAML) cve-2025-62495.yaml
id: cve-2025-62495

info:
  name: quickjs_project quickjs - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2025-62495 affecting quickjs_project quickjs.
    Evaluation: An integer overflow vulnerability exists in the QuickJS regular expression engine (libregexp) due to an inconsistent representation of the bytecode bu...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2025-62495
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.8
    cve-id: CVE-2025-62495
    cwe-id: CWE-191
  tags: cve,cve-2025-62495,quickjs_project,quickjs,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "quickjs"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2025-62495.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2025-62495
# Target: quickjs_project quickjs | CVSS: 8.8 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2025-62495 (quickjs_project quickjs)...")
    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 quickjs_project quickjs 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-2025-62495.sh
# Recommended Remediation & Patching Commands for CVE-2025-62495
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install quickjs 2>/dev/null || \
sudo dnf upgrade quickjs 2>/dev/null || \
sudo yum update quickjs

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

# 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-2025-62495 in quickjs_project quickjs?

Review vendor-specific security notices and update quickjs_project quickjs 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-2025-62495?

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-2025-62495?

CVE-2025-62495 is classified with a CVSS 3.1 Base Score of 8.8 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.8
HIGH SEVERITY
CVE ID CVE-2025-62495
Weakness CWE-191
Vendor quickjs_project
Product quickjs
Published 2025-10-16
Vector CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H