What’s Vulnerable › Vulnerabilities

CVE-2026-43888: Outline: Zip Extraction Path Escape via PATH_MAX Truncation in Collection Import

• Severity: high (CVSS 8.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-11 · updated 2026-06-17
• Weakness: CWE-22

Description

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.

Affected products

• outline: before 1.7.0

References

• https://github.com/outline/outline/security/advisories/GHSA-hw32-2v7j-mgqc
• https://github.com/outline/outline/security/advisories/GHSA-hw32-2v7j-mgqc

Get alerted when CVE-2026-43888 or the next vulnerability affects your stack