Unauthenticated file overwrite via import-name traversal
Published Sep 7, 2026 · Updated Sep 8, 2026
Path traversal in Knowns before 0.30.0 allows remote attackers to overwrite files writable by the server via crafted import names. The REST import handlers in internal/server/routes/imports.go pass the untrusted name field to filepath.Join without checking that the resolved destination remains under the imports directory. Any network-reachable instance exposes the overwrite without authentication, and writable configuration or executable paths can turn the file write into code execution.
Summary
What happened
Path traversal in Knowns before 0.30.0 allows remote attackers to overwrite files writable by the server via crafted import names. The REST import handlers in internal/server/routes/imports.go pass the untrusted name field to filepath.Join without checking that the resolved destination remains under the imports directory. Any network-reachable instance exposes the overwrite without authentication, and writable configuration or executable paths can turn the file write into code execution.
The record
- CVE
- CVE-2026-86542
- Published
- Sep 7, 2026
- Updated
- Sep 8, 2026
- Vendor
- Knowns
- Product
- Knowns
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 7, 2026CVE publishedPublication date reported by the CVE source.
- Sep 8, 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=0 <0.30.0
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
- Unauthenticated REST API path traversal and LSP binary override chainproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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