CVE-2026-53798
Description
A privilege confusion vulnerability in rsync's name-converter subprocess allows a local attacker to achieve privilege escalation. By manipulating the subprocess to return empty values for uid or gid lookups, the attacker forces rsync to incorrectly interpret these as root (uid/gid 0). Consequently, transferred files are improperly assigned root ownership.
Statement
A Moderate severity privilege escalation vulnerability exists in rsync. A local attacker can manipulate the name-converter subprocess to return empty user ID (uid) or group ID (gid) values. This manipulation causes rsync to incorrectly assign root ownership to transferred files, resulting in elevated privileges for the attacker.
Mitigation
Do not set name converter in rsyncd.conf unless you need chroot uid/gid lookups, and do not enable fake super unless you need it. Restrict rsyncd (TCP 873) to trusted clients; if the daemon is unused, disable rsyncd.service. If both options are required, keep the service on a trusted network
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 | 5.3 | N/A | 5.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
A user can access restricted functionality and/or sensitive information that may include administrative functionality and user accounts.
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