Deserialization of Untrusted DataWeakness · CWE-502

CVE-2026-25360

HIGH · 8.8 CVSS v3.1 Published 2026-03-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
Deserialization of Untrusted Data vulnerability in rascals Vex vex allows Object Injection.This issue affects Vex: from n/a through < 1.2.9.

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 · moderate confidence

Deserialization of Untrusted Data vulnerability in the Vex library (rascals/Vex) allows Object Injection. This is a code injection vulnerability where untrusted data deserialized by the application can be manipulated to instantiate arbitrary objects, potentially leading to remote code execution. The issue affects all versions prior to 1.2.9.

MitigationUpgrade the Vex library to version 1.2.9 or later. Review any deserialization paths in code using this library and ensure external input is validated before deserialization.

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/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 the installed Vex library version
    Locate the Vex library in your project's dependency manifest (such as package.json for Node.js, Gemfile for Ruby, composer.json for PHP, or requirements.txt for Python) and note the version number specified. If using a package manager, you can also run a version query command (for example, 'npm list vex' or 'pip show vex') to retrieve the installed version.
    Affected if The version is lower than 1.2.9 or no version is specified (implying an unpatched release).
  2. Determine if deserialization is used in your codebase
    Search your application source code for usage of deserialization functions that process data from the Vex library. Look for patterns such as unserialize(), json_decode() when used with untrusted input, YAML parsing of external data, or similar deserialization calls. Review any endpoints or functions that accept serialized data and pass it to the Vex library.
    Affected if Your application deserializes data from untrusted sources using the Vex library, and the library version is below 1.2.9.
  3. Review Vex library usage in your application
    Examine the files where the Vex library is imported or referenced. Check if the library is used to parse, render, or process content that could originate from user input, external APIs, or uploaded files. Look for any code paths where external data flows into Vex library functions.
    Affected if The Vex library processes untrusted input and the installed version is prior to 1.2.9.

You are affected if your installed Vex library version is below 1.2.9 AND your application uses the library to deserialize or process data from untrusted sources.

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 the Vex library to version 1.2.9 or later. Review any deserialization paths in code using this library and ensure external input is validated before deserialization.

Recommended fix Moderate confidence

Upgrade to Vex version 1.2.9 or later

  1. Identify the current version of Vex library/package being used in the project
  2. Upgrade Vex to version 1.2.9 or later by updating the dependency in your project's package manager (e.g., npm, pip, or gem depending on the language)
  3. Run the upgrade command (e.g., npm update vex, pip install --upgrade vex, or gem update vex)
  4. Verify the new version is installed by checking the installed package version
  5. Restart any services or applications using the Vex library
  6. Test the application functionality to ensure the upgrade does not break existing features
Caveat Review the changelog between your current version and 1.2.9 for any breaking changes in API or behavior

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

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,190
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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-2026-25360 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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