CVE-2026-53791
Description
A flaw in rsync allows an unauthenticated remote attacker to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source IP address, granting unauthorized access to restricted resources.
Statement
A flaw was found in the rsync daemon. When configured to use the PROXY protocol, an unauthenticated remote attacker can bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source IP address. This allows unauthorized access to restricted resources.
Note: Red Hat Enterprise Linux 8 and earlier versions do not contain the vulnerable PROXY protocol implementation and are not affected.
Mitigation
Restrict rsync daemon TCP/873 to the trusted proxy only (CME-202). If PROXY protocol is unused, leave proxy protocol disabled (the default).
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.4 | N/A | 9.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
This weakness can allow an attacker to access resources which are not otherwise accessible without proper authentication.
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