CVE-2026-70453
Description
A flaw was found in rsync. A remote attacker can exploit an algorithmic complexity vulnerability within the hash_search() function by sending a specially crafted file list. This can lead to the exhaustion of the receiver's CPU resources, causing a sustained denial of service (DoS).
Statement
This Moderate flaw in rsync's hash_search() function allows a remote attacker to cause a denial of service. By sending a specially crafted file list, an attacker can exhaust the receiver's CPU resources, leading to service unavailability. This is particularly relevant in Red Hat environments where rsync is used for remote file synchronization and may be exposed to untrusted networks.
Mitigation
Disable unused rsyncd services (systemctl disable --now rsyncd), or restrict daemon access to trusted clients via hosts allow and firewall rules. Avoid synchronizing with untrusted senders or pushing to untrusted receivers and upload modules to prevent processing malicious file lists. To contain potential Denial of Service, enforce CPU resource limits on rsync processes using systemd cgroups or ulimit -t to prevent a quadratic search walk from starving the host.
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 | 6.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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