Vulnerability · Published Jun 11, 2026 · Assigned by GitHub_M
CVE-2026-49982tmp: Type-confusion bypass of _assertPath in tmp@0.2.6 allows path traversal via non-string prefix/postfix/template
High 8.2
In plain English
A high-severity improper input validation in node-tmp from raszi. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
tmp is a temporary file and directory creator for node.js. In version 0.2.6, the _assertPath guard added to tmp rejects only string values that contain the substring ... It is bypassed when prefix, postfix, or template is supplied as a non-string value (Array, Buffer, or any object) whose includes('..') returns falsy but whose stringification still contains ../. The value flows through Array.prototype.join/String coercion inside _generateTmpName and path.join(tmpDir, opts.dir, name), producing a final path that escapes tmpdir and creates a file or directory at an attacker-controlled location with the host process's privileges. This affects any application that forwards untrusted request data (a common pattern is JSON body fields or qs-parsed bracket-array query strings such as ?prefix[]=...) into tmp.file, tmp.fileSync, tmp.dir, tmp.dirSync, tmp.tmpName, or tmp.tmpNameSync without explicit type coercion. This vulnerability is fixed in 0.2.7.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | node-tmp | no fix listed | UBUNTU-CVE-2026-49982 |
| Ubuntu:24.04:LTS | node-tmp | no fix listed | UBUNTU-CVE-2026-49982 |
| Ubuntu:25.10 | node-tmp | no fix listed | UBUNTU-CVE-2026-49982 |
| Ubuntu:26.04:LTS | node-tmp | no fix listed | UBUNTU-CVE-2026-49982 |
| Ubuntu:26.10 | node-tmp | no fix listed | UBUNTU-CVE-2026-49982 |
| npm | tmp | 0.2.7 | GHSA-7c78-jf6q-g5cm |
Affected products (as reported)
Weakness: CWE-20, CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
References
- https://github.com/raszi/node-tmp/security/advisories/GHSA-7c78-jf6q-g5cm x_refsource_CONFIRM