CVE-2026-55499 Cloudreve: Broken Access Control in file event stream: a single-file share recipient is subscribed to the owner's parent folder and receives activity events for unshared siblings
Authenticated share recipients can view metadata of unshared sibling files due to broken access control in the event stream.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55499?
CVE-2026-55499 is a medium-severity vulnerability in cloudreve, published on 31 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Cloudreve is a self-hosted file management and sharing system. Prior to 4.17.0, a single-file share event-stream subscription resolves the share root to the owner’s parent folder and subscribes to that folder topic, allowing an authenticated share recipient to receive names, paths, rename targets, event types, and hashed identifiers for unshared sibling files and folders. This issue is fixed in version 4.17.0.
Weakness: CWE-863
Which versions are affected by CVE-2026-55499?
7 open source packages ship an affected version, including github.com/cloudreve/Cloudreve/v3, github.com/cloudreve/Cloudreve and github.com/cloudreve/Cloudreve/v4.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cloudreve/Cloudreve/v3 Go | All versions | None |
github.com/cloudreve/Cloudreve/v3 Go | All versions to 3.0.0-20250225100611-da4e44b77af4 | None |
github.com/cloudreve/Cloudreve/v3 Go | All versions to 3.0.0-20250225100611-da4e44b77af4 | None |
github.com/cloudreve/Cloudreve Go | All versions | None |
github.com/cloudreve/Cloudreve/v4 Go | All versions | 4.0.0-20260613030215-0b00dd308f13 |
github.com/cloudreve/Cloudreve/v4 Go | All versions | 4.0.0-20260613030215-0b00dd308f13 |
1 more packages
github.com/cloudreve/Cloudreve/v4 Go | All versions | 4.0.0-20260613030215-0b00dd308f13 |
How do I fix CVE-2026-55499?
Upgrade to a fixed version.
Is CVE-2026-55499 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55499 exists.
Sources
Also known as GHSA-w8x7-h2px-xmq8, GO-2026-6102.