CVE-2026-43888CWE-22

Outline: Zip Extraction Path Escape via PATH_MAX Truncation in Collection Import

High · published May 11, 2026

CVSS v3.1
8.7
EPSS
1%
Percentile
43.1
In the wild
Unconfirmed
What it is

Outline is a service that allows for collaborative documentation. Prior to 1.7.0, ZipHelper.extract computes the extraction path for each entry by passing a full filesystem path through trimFileAndExt, a filename helper that calls path.basename on its input when truncating. When a zip entry's nested path is long enough to push the joined filesystem path over MAX_PATH_LENGTH (4096 bytes), trimFileAndExt silently drops all directory components and returns a bare filename. fs.createWriteStream then opens the file relative to the process working directory instead of inside the extraction sandbox, and the escaped file persists after import cleanup because cleanupExtractedData only removes the temporary extraction directory. This vulnerability is fixed in 1.7.0.

The record
Technical detail
CVSS v3.1
8.7 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00517 · 43.1th percentile
Weakness
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Published
2026-05-11T21:09Z
EPSS history
Timeline
  • 11 MAY 21:09Z
    Outline: Zip Extraction Path Escape via PATH_MAX Truncation in Collection Import
    cvelistv5