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Deserialization of Untrusted DataWeakness · CWE-502

CVE-2026-42473

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
Unsafe deserialization vulnerability in MixPHP Framework 2.x thru 2.2.17. The session and cache handlers use unserialize() on data from the filesystem in the FileHandler object.

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

The MixPHP Framework 2.x through 2.2.17 contains an unsafe deserialization vulnerability in the FileHandler object used for session and cache storage. The handlers call unserialize() on data read from filesystem files without validating the data source or integrity, potentially allowing remote code execution if an attacker can inject malicious serialized payloads into session or cache files.

MitigationUpgrade to a patched version of MixPHP Framework or replace the unsafe unserialize() calls in FileHandler with safe deserialization methods (e.g., JSON encoding) and add integrity verification (HMAC signatures) for stored session/cache data.

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

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 MixPHP Framework installation and version
    Locate the MixPHP installation and check its version number in composer.json, a version.php file, or by running 'composer show mixphp/framework' if composer is available. Look for version numbers in the 2.x range up to and including 2.2.17.
    Affected if The installed version is 2.x through 2.2.17 (any version from 2.0 to 2.2.17 inclusive).
  2. Identify if FileHandler is used for session storage
    Examine the session configuration file (commonly in config/session.php or similar) and look for a handler configuration setting. Check if the handler class is set to 'FileHandler' or a class path containing 'FileHandler'.
    Affected if FileHandler is configured as the session handler.
  3. Identify if FileHandler is used for cache storage
    Examine the cache configuration file (commonly in config/cache.php or similar) and look for store or handler settings. Check if the cache driver or handler is set to 'FileHandler' or uses file-based storage.
    Affected if FileHandler is configured as the cache handler or driver.
  4. Locate session and cache storage directories
    Find the directories where session and cache files are stored. This is typically configured in the session/cache config files (look for 'path', 'save_path', or 'directory' settings). Default locations may include runtime/session, runtime/cache, or tmp directories.
    Affected if Session or cache files are stored in a directory that may be writable by the web server user or other untrusted users.
  5. Inspect FileHandler source code for unsafe unserialize
    Locate the FileHandler class file in the MixPHP installation (commonly under src/Cache/FileHandler.php or similar paths). Open the file and search for calls to unserialize() function.
    Affected if The FileHandler code contains unserialize() calls without prior integrity validation (such as HMAC signature checks) or input source validation.

A user is affected if they are running MixPHP Framework version 2.0 through 2.2.17 and have FileHandler enabled for session or cache storage, with the vulnerable unserialize() calls present in the code.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to a patched version of MixPHP Framework or replace the unsafe unserialize() calls in FileHandler with safe deserialization methods (e.g., JSON encoding) and add integrity verification (HMAC signatures) for stored session/cache data.

Recommended fix Moderate confidence

MixPHP Framework 2.2.18 or latest stable 2.x release

  1. Check the currently installed MixPHP Framework version by examining composer.json or the installed version
  2. If running version 2.x through 2.2.17, update to the latest stable version (2.2.18 or later) using: composer require mixphp/mixphp:^2.2.18 or composer update mixphp/mixphp
  3. After upgrading, verify the FileHandler class no longer uses unserialize() on untrusted data - check that the session and cache handlers now use a safe serialization method
  4. Restart any PHP-FPM or application processes to load the updated version
  5. Test that session and cache functionality works correctly with the new version
Caveat Minor - the upgrade addresses a security vulnerability; ensure session/cache functionality works after updating

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

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2026-42473 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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