Arbitrary file write via overlong ZIP paths
Published May 11, 2026 · Updated May 11, 2026
Path traversal in Outline before 1.7.0 allows remote authenticated users to write arbitrary files through collection import. ZipHelper.extract passes a joined extraction path exceeding 4,096 bytes to trimFileAndExt, which applies path.basename and gives fs.createWriteStream a bare filename outside the extraction directory. Team-administrator access and a specially sized ZIP entry are required; the escaped file persists and can overwrite application files, interrupt service, or execute code after restart.
Summary
What happened
Path traversal in Outline before 1.7.0 allows remote authenticated users to write arbitrary files through collection import. ZipHelper.extract passes a joined extraction path exceeding 4,096 bytes to trimFileAndExt, which applies path.basename and gives fs.createWriteStream a bare filename outside the extraction directory. Team-administrator access and a specially sized ZIP entry are required; the escaped file persists and can overwrite application files, interrupt service, or execute code after restart.
The record
- CVE
- CVE-2026-43888
- Published
- May 11, 2026
- Updated
- May 11, 2026
- Vendor
- Outline
- Product
- Outline
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- May 11, 2026CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.7.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-hw32-2v7j-mgqc collection-import proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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