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PHPApplication

CVE-2023-0662

HIGH · 7.5 CVSS v3.1 Published 2023-02-16
Fix available
A fix is available. Upgrade to 8.0.28 / 8.1.16 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In PHP 8.0.X before 8.0.28, 8.1.X before 8.1.16 and 8.2.X before 8.2.3, excessive number of parts in HTTP form upload can cause high resource consumption and excessive number of log entries. This can cause denial of service on the affected server by exhausting CPU resources or disk space.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a denial of service vulnerability in PHP's multipart form upload handling. When an HTTP request contains an excessively large number of parts in a multipart form upload, PHP consumes excessive CPU resources processing these parts and generates voluminous log entries, potentially exhausting disk space. The vulnerability affects PHP 8.0 before 8.0.28, 8.1 before 8.1.16, and 8.2 before 8.2.3.

MitigationUpgrade PHP to version 8.0.28, 8.1.16, 8.2.3 or later. Additionally, configure web server-level limits on multipart form part counts and request sizes, and implement rate limiting at the application or network edge to mitigate exploitation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PHPApplication
Affected:>= 8.0.0, < 8.0.28>= 8.1.0, < 8.1.16>= 8.2.0, < 8.2.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed PHP version
    Run `php -v` on the command line or call `phpinfo()` in a web script to retrieve the PHP version number
    Affected if The version is 8.0.0 through 8.0.27, 8.1.0 through 8.1.15, or 8.2.0 through 8.2.2
  2. Confirm PHP multipart form handling is enabled
    Check php.ini for `file_uploads = On` and verify the presence of multipart form handling functions in the PHP installation
    Affected if File uploads are enabled and the application uses multipart form processing (forms with enctype="multipart/form-data" or PHP file upload functions)
  3. Check PHP configuration limits for form parts
    Review php.ini or script output for `post_max_size`, `max_file_uploads`, and any custom multipart form part limits
    Affected if No explicit limits are set on the number of multipart form parts or the request size is set very high (e.g., post_max_size > 8MB)
  4. Inspect application for multipart form usage
    Search application code for forms using enctype="multipart/form-data" or PHP file upload handling (move_uploaded_file, $_FILES)
    Affected if The application processes multipart form uploads and runs on a vulnerable PHP version

A user is affected if they run a vulnerable PHP version (8.0.0-8.0.27, 8.1.0-8.1.15, or 8.2.0-8.2.2) AND the application accepts multipart form uploads, as an attacker could send requests with excessively large numbers of form parts to exhaust CPU and disk space.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.0.28 / 8.1.16 / 8.2.3 or later
Fixed in 8.0.288.1.168.2.3
Interim mitigation

Upgrade PHP to version 8.0.28, 8.1.16, 8.2.3 or later. Additionally, configure web server-level limits on multipart form part counts and request sizes, and implement rate limiting at the application or network edge to mitigate exploitation.

Recommended fix High confidence

PHP 8.0.28, 8.1.16, or 8.2.3 (or later)

  1. Check current PHP version using 'php -v' or phpinfo()
  2. Backup all PHP configuration files and any application code that depends on specific PHP behavior
  3. For Ubuntu/Debian: Run 'sudo apt update && sudo apt upgrade php' or specify version: 'sudo apt install php8.0=8.0.28*' or 'sudo apt install php8.1=8.1.16*' or 'sudo apt install php8.2=8.2.3*'
  4. For RHEL/CentOS: Run 'sudo yum update php' or 'sudo dnf update php'
  5. For Windows: Download the specific fixed version from windows.php.net
  6. After upgrade, restart the web server (Apache: 'sudo systemctl restart apache2', Nginx: 'sudo systemctl restart php-fpm' and 'sudo systemctl restart nginx')
  7. Verify the new PHP version with 'php -v' to confirm it matches 8.0.28, 8.1.16, 8.2.3 or later
  8. Test critical application functionality to ensure compatibility with the upgraded PHP version
Caveat Minor PHP version upgrades may introduce subtle behavioral changes; test applications thoroughly before deploying to production

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in PHP Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-0662 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data