Cloudreve Security Update Addresses 3 Vulnerabilities
Tech GuruQuick Answer
Cloudreve 4.18.0 is the project-listed fix for three issues affecting versions through 4.17.0: concurrent uploads can exceed storage quotas, an Admin.Read OAuth token can invoke two write-like admin tools, and remote-download URL checks can miss certain IPv6-wrapped internal addresses. Inventory the running application and these permissions before choosing a supported release that contains the fixes.
Confirm Scope And Apply The Supported Fix
What to do now: update affected Cloudreve servers through the official channel. While arranging the change, restrict uploads and remote downloads to trusted users, review read-only admin tokens, and monitor storage headroom. Network egress restrictions are additional containment, not proof that the URL validator is patched.
Source recheck: October 2, 2026 UTC. The linked project advisories were checked for this revision; deployment applicability and successful remediation still require local evidence. Recheck the supported release before changing production.
Scope And Authority
| Product scope | Cloudreve packages and release streams identified in the project advisories |
|---|---|
| Advisory | GHSA-xj3h-wwxq-gfcj / GHSA-w89x-c962-c44g / GHSA-jvh5-97xg-v99f |
| CVEs | CVE-2026-77633, CVE-2026-77637, CVE-2026-79913 |
| Authoritative release date | 2026-09-14 UTC (project advisory dates, not database ingestion) |
| Authority revision date | 2026-09-14 UTC (project advisory dates, not database ingestion) |
| Affected versions | Cloudreve <=4.17.0, according to all three primary project advisories. Match the application build as well as any embedded Go module. |
| Fixed version | Cloudreve 4.18.0 is the listed application fix for all three issues. Select a supported release containing these and later applicable fixes; Go commit pseudo-versions are not a substitute for confirming the installed application release. |
| CVSS base score | Published structured CVSS v3.1 fields: quota race 7.1; OAuth scope bypass 3.8; SSRF 6.5. The SSRF report narrative proposes 8.3, which differs from its published structured rating. |
| CVSS severity | Low to High |
| Exploitation status | Not stated by the authority; no exploitation claim is inferred. |
What Changed
CVE-2026-77633 separates quota checking from reservation, allowing concurrent Files.Write upload requests to approve excess capacity; completing those uploads can exhaust storage. CVE-2026-77637 lets an Admin.Read token invoke the WOPI probe and test-mail tools without Admin.Write. CVE-2026-79913 affects authenticated remote downloads when IPv6-transition addresses route to internal IPv4 destinations. Its report demonstrates guard acceptance but emulates the final network hop, so it is not evidence of credential theft from a real cloud deployment.
What To Validate Now
- Inventory. Record Cloudreve release/build, storage policies and free space, Files.Write users, Admin.Read OAuth applications, remote-download permissions and server egress routes.
- Establish applicability. Apply the primary through-4.17.0 range. Evaluate the upload race, read-only admin tools and remote-download routing separately; removing one permission does not fix the other paths.
- Remediate. Install a supported Cloudreve release containing the 4.18.0 fixes, following the official upgrade and backup procedure. Do not treat one Go pseudo-version from the old table as an application update covering all three issues.
- Validate. Use staging, disposable low-quota accounts, a mail sink and synthetic internal endpoints to verify quota enforcement, write-scope checks and download boundaries. Do not fill production storage, send test messages to real recipients or retrieve cloud credentials.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
Use the exact supported release stream and repository. Test dependencies, clusters, integrations, and rollback before broad deployment; a CVSS rating or reachable feature is not evidence of exploitation.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
