CVE-2026-43888

High

Published: 11 May 2026

Published

11 May 2026

Modified

12 May 2026

KEV Added

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Patch

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CVSS Score v3.1 8.7 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:H

EPSS Score 0.0037 28.8th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-43888 is a high-severity Path Traversal (CWE-22) vulnerability. Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 28.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-29332

Vulnerability details

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.

CWE(s): CWE-22

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Path traversal in public-facing Outline zip import (CWE-22) directly enables arbitrary file write outside sandbox, matching exploitation of exposed application.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0