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Classic Buffer OverflowWeakness · CWE-120

CVE-2025-55131

HIGH · 7.1 CVSS v3.1 Published 2026-01-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
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
A flaw in Node.js's buffer allocation logic can expose uninitialized memory when allocations are interrupted, when using the `vm` module with the timeout option. Under specific timing conditions, buffers allocated with `Buffer.alloc` and other `TypedArray` instances like `Uint8Array` may contain leftover data from previous operations, allowing in-process secrets like tokens or passwords to leak or causing data corruption. While exploitation typically requires precise timing or in-process code execution, it can become remotely exploitable when untrusted input influences workload and timeouts, leading to potential confidentiality and integrity impact.

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

A flaw in Node.js's buffer allocation logic exposes uninitialized memory when buffer allocations are interrupted, specifically when using the `vm` module with the timeout option. Under specific timing conditions, buffers allocated with `Buffer.alloc` and other TypedArray instances like `Uint8Array` may contain leftover data from previous operations, potentially leaking in-process secrets or causing data corruption.

MitigationAvoid using the `vm` module with timeout options when handling sensitive data, and ensure buffers are explicitly initialized/zeroed before use until a patched Node.js version is available.

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

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

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 Node.js version
    Run `node --version` to get the installed Node.js version
    Affected if The version is within the affected range and has not yet received the security fix for this CVE
  2. Search for vm module usage with timeout
    Search codebases for patterns like `vm.compileFunction`, `vm.runInContext`, or `vm.Script` combined with a timeout option - inspect configuration files, application code, and dynamically loaded modules
    Affected if The vm module is used with a timeout option in the application or any imported module
  3. Identify buffer operations following vm timeout
    Review code that uses Buffer.alloc, Buffer.allocUnsafe, Buffer.from, Uint8Array, or other TypedArrays after vm module operations with timeout - search for sequential execution patterns
    Affected if Buffer allocation or TypedArray instantiation occurs in code paths that execute after vm timeout operations handling sensitive data
  4. Check for sensitive data in process memory
    Audit whether the application processes secrets, credentials, tokens, keys, PII, or other sensitive data in the same Node.js process that uses vm with timeout
    Affected if Sensitive data exists in the same process memory where vm timeout and buffer operations are used together

A user is affected if they run a Node.js version within the CVE's affected range and their code uses the vm module with timeout options while simultaneously allocating buffers or TypedArrays in the same execution context with sensitive data present.

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

Avoid using the `vm` module with timeout options when handling sensitive data, and ensure buffers are explicitly initialized/zeroed before use until a patched Node.js version is available.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,760
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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-2025-55131 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
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