9.8Critical

Rollupjs Rollup

CVE-2026-27606

Rollup is a module bundler for JavaScript. Versions prior to 2.80.0, 3.30.0, and 4.59.0 of the Rollup module bundler (specifically v4.x and present in current source) is vulnerable to an Arbitrary File Write via Path Traversal. Insecure file name sanitization in the core engine allows an attacker to control output filenames (e.g., via CLI named inputs, manual chunk aliases, or malicious plugins) and use traversal sequences (`../`) to overwrite files anywhere on the host filesystem that the build process has permissions for. This can lead to persistent Remote Code Execution (RCE) by overwriting critical system or user configuration files. Versions 2.80.0, 3.30.0, and 4.59.0 contain a patch for the issue.

What this means for your business

  • It affects Rollupjs Rollup. It matters if your company, or a supplier that handles your data, runs it.
  • Code showing how to exploit it has been published, but real attacks have not been confirmed.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 1% chance of attack attempts being seen in the next 30 days, ranking above 71% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run Rollupjs Rollup, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Scoring

CVSS
9.8 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4
8.8
Weakness
CWE-22
Assigned by
security-advisories@github.com

Dates

Published
2026-02-25
Last modified
2026-09-10
Sources
NVD

Affected products

  • Rollupjs Rollup- 2.80.0, 3.0.0 - 3.30.0, 4.0.0 - 4.59.0

As listed in the NVD configuration data. Not a statement about your estate.

References