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PatchSiren cyber security CVE debrief

CVE-2026-62323 cloudreve CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-31T04:17:24.160Z and has not been modified since then. 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. The vulnerability allows a malicious WOPI viewer with a view session to forge the token suffix and invoke WOPI write routes for the underlying file. Administrators should verify WOPI access token validation in Cloudreve and monitor for suspicious WOPI viewer activity.

Vendor
cloudreve
Product
cloudreve
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-31
Original CVE updated
2026-07-31
Advisory published
2026-07-31
Advisory updated
2026-07-31

Who should care

Administrators and users of Cloudreve versions prior to 4.17.0 should review and apply the patch to prevent potential exploitation. This includes operators, security teams, and vulnerability management teams responsible for ensuring the security of Cloudreve deployments. They should verify WOPI access token validation in Cloudreve and monitor for suspicious WOPI viewer activity.

Technical summary

Cloudreve's ViewerSessionValidation uses only the session-id prefix of a WOPI access token and does not enforce the requested viewer action. This allows a malicious WOPI viewer with a view session to forge the token suffix and invoke WOPI write routes for the underlying file. The issue is fixed in version 4.17.0. Administrators and users of Cloudreve versions prior to 4.17.0 should review and apply the patch to prevent potential exploitation.

Defensive priority

Medium-priority defensive actions are recommended due to the CVSS score of 6.3 and the potential for malicious WOPI viewers to invoke write routes.

Recommended defensive actions

  • Review and apply the patch in version 4.17.0
  • Verify WOPI access token validation in Cloudreve
  • Monitor for suspicious WOPI viewer activity
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and NVD detail provide information on the vulnerability in Cloudreve's ViewerSessionValidation. Evidence is based on official records from CVE.org and the NVD. The vulnerability allows a malicious WOPI viewer with a view session to forge the token suffix and invoke WOPI write routes for the underlying file. Administrators should verify WOPI access token validation in Cloudreve and monitor for suspicious WOPI viewer activity. The issue is fixed in version 4.17.0.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-31T04:17:24.160Z and has not been modified since then.