CVE-2026-53791
Critical
Description
rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.
SeverityCritical
CVSS9.1
Exploit probability—
ProductSamba Rsync
PublishedAug 13, 2026
First seenAug 13, 2026
Weakness typeCWE-290CWE-290
How to fix
Update
- samba rsync3.5.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| samba rsync | v < 3.5.0 | 3.5.0 |
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