Authenticated file writes via WOPI path traversal
Published Jul 31, 2026 · Updated Jul 31, 2026
Path traversal in Cloudreve before 4.17.0 allows remote authenticated users to create or conditionally overwrite files in their accounts. The PUT_RELATIVE handler splits the X-WOPI-SuggestedTarget header and gives its path segments to URI.JoinRaw, whose URL normalization resolves dot-dot segments before basename validation. A WOPI token scoped to one owned file is required; traversal remains within that account but defeats the token's per-file boundary.
Summary
What happened
Path traversal in Cloudreve before 4.17.0 allows remote authenticated users to create or conditionally overwrite files in their accounts. The PUT_RELATIVE handler splits the X-WOPI-SuggestedTarget header and gives its path segments to URI.JoinRaw, whose URL normalization resolves dot-dot segments before basename validation. A WOPI token scoped to one owned file is required; traversal remains within that account but defeats the token's per-file boundary.
The record
- CVE
- CVE-2026-55495
- Published
- Jul 31, 2026
- Updated
- Jul 31, 2026
- Vendor
- Cloudreve
- Product
- Cloudreve
- Classifications
- CWE-22, T1565.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 31, 2026CVE publishedPublication date reported by the CVE source.
- Jul 31, 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=< 4.17.0
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-49h3-cwhj-4737 WOPI PUT_RELATIVE reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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