Deserialization of Untrusted DataWeakness · CWE-502

CVE-2026-40044

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-13
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
Pachno 1.0.6 contains a deserialization vulnerability that allows unauthenticated attackers to execute arbitrary code by injecting malicious serialized objects into cache files. Attackers can write PHP object payloads to world-writable cache files with predictable names in the cache directory, which are unserialized during framework bootstrap before authentication checks occur.

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

Pachno 1.0.6 suffers from an insecure deserialization vulnerability where unauthenticated attackers can inject malicious PHP serialized objects into world-writable cache files with predictable names. These cache files are deserialized during framework bootstrap before any authentication occurs, allowing remote code execution.

MitigationRestrict cache file permissions to prevent unauthenticated write access, implement validation/deserialization guards before processing cached data, and consider migrating from PHP serialize() to safer formats like JSON for cache storage.

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 installed Pachno version
    Check the version file in the Pachno installation directory, typically found in a version.php file or the application header/admin panel. Compare against version 1.0.6.
    Affected if The installed version is 1.0.6 or the version cannot be determined but the software is Pachno.
  2. Inspect cache directory permissions
    Locate the cache directory (commonly 'cache' or 'data/cache' within the Pachno installation). Use 'ls -la' to check file permissions. Verify if cache files or their parent directory are world-writable (permissions ending in 777 or containing 'other' write bits).
    Affected if Cache files or the cache directory have world-writable permissions (mode 0777 or writable by 'others').
  3. Check for cache file existence
    List contents of the cache directory. Look for cache files with predictable/named patterns (common in frameworks like Twig caches or application caches).
    Affected if Cache files exist and are stored in a publicly accessible directory with predictable filenames.
  4. Examine PHP deserialization usage
    Search the application bootstrap files (index.php, bootstrap.php, or similar) for calls to unserialize() function that process cached data without prior validation.
    Affected if The application uses unserialize() on cache file contents during bootstrap before any authentication check.
  5. Verify unauthenticated cache write access
    Test or inspect whether the web server process (or other non-privileged users) can write to the cache directory. Check directory ownership and permissions relative to the web server user.
    Affected if The web server user or unauthenticated remote attackers can create or modify files in the cache directory.

A Pachno 1.0.6 installation with world-writable cache directories that deserialize data during bootstrap is vulnerable to unauthenticated RCE via insecure deserialization.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict cache file permissions to prevent unauthenticated write access, implement validation/deserialization guards before processing cached data, and consider migrating from PHP serialize() to safer formats like JSON for cache storage.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-40044 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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