What’s Vulnerable › Vulnerabilities

CVE-2026-62323: Cloudreve: Unauthorized file write via WOPI view sessions whose access token secret is ignored

• Severity: medium (CVSS 6.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-31 · updated 2026-09-08
• Weakness: CWE-863

Description

Cloudreve is a self-hosted file management and sharing system. Prior to 4.17.0, ViewerSessionValidation uses only the session-id prefix of a WOPI access token and does not enforce the requested viewer action, allowing a malicious or compromised WOPI viewer with a view session to forge the token suffix and invoke WOPI write routes for the underlying file. This issue is fixed in version 4.17.0.

Affected products

• cloudreve: before 4.17.0

References

• https://github.com/cloudreve/cloudreve/commit/f3347130ac48f2ff996af9ef66c97be2dda9cba9
• https://github.com/cloudreve/cloudreve/releases/tag/4.17.0
• https://github.com/cloudreve/cloudreve/security/advisories/GHSA-c3jm-gv5r-9wcp
• https://github.com/cloudreve/cloudreve/security/advisories/GHSA-c3jm-gv5r-9wcp

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