CVE-2026-49982: raszi node-tmp path traversal bypass via type confusion

CVE-2026-49982 · Severity: high · CVSS 8.2 · Published 2026-06-11

The 'tmp' library, a popular Node.js package for creating temporary files and directories, contains a vulnerability that allows attackers to create files in unauthorized locations on a server. By providing specially crafted input (such as an array instead of a string) to the library's functions, an attacker can bypass security checks and write data outside of the intended temporary folder. This could lead to the corruption of sensitive system files, unauthorized data placement in web roots, or service disruptions.

Technologies: tmp (npm). Vendors: npm.

Quick answers

Is CVE-2026-49982 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-49982 being exploited in the wild.
How severe is CVE-2026-49982?
High severity, with a CVSS score of 8.2, published 11 June 2026.
Which products and versions are affected?
tmp (npm) >= 0.2.6, < 0.2.7, SEMVER:introduced=0.2.6,fixed=0.2.7.
Is there a fix for CVE-2026-49982?
Yes. tmp (npm): upgrade to 0.2.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-49982 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-49982?
Check whether you run tmp (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • tmp (npm): upgrade to 0.2.7 or later
    npm install tmp@0.2.7

Technical details

A type-confusion vulnerability exists in the `_assertPath` function of the `tmp` library. The function intended to block path traversal by checking for the `..` substring, but it assumes the input is always a string. When an attacker provides a non-string value (such as an Array or an Object with a custom `includes` method), the check can be bypassed. Subsequent string coercion during path construction (via `Array.prototype.join` or `path.join`) reintroduces the traversal sequence. This allows an attacker to escape the designated temporary directory and create files or directories anywhere the process has write permissions. The vulnerability is reachable over the network if an application passes untrusted request data (e.g., from JSON bodies or query strings) directly into `tmp` library functions like `tmp.file()` or `tmp.dir()`. A fix is available in version 0.2.7 which enforces string type checking.

Affected products

  • raszi tmp >= 0.2.6, < 0.2.7

Identifiers

  • CVE-2026-49982
  • GHSA-7c78-jf6q-g5cm

Timeline

  • 2026-05-27: disclosed
  • 2026-06-15: advisory

References

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