CVE-2026-70457
Description
An out-of-bounds write vulnerability in rsync's parse_size_arg() function allows a remote attacker to cause memory corruption. The flaw is triggered when snprintf() truncates a formatted size string, resulting in an incorrect memory array index. Exploitation can lead to a denial of service and potentially compromise data integrity.
Statement
This Moderate impact flaw in rsync stems from an out-of-bounds write in the parse_size_arg() function. Although no privileges or user interaction are required, the high attack complexity indicates that exploitation is not straightforward. Successful exploitation could lead to memory corruption, potentially causing a denial of service or compromising data integrity on affected Red Hat systems.
Mitigation
If rsync is configured to run as a daemon, restrict network access to trusted hosts using firewall rules. For example, to limit access to localhost:
`firewall-cmd --permanent --add-rich-rule='rule family="ipv4" port port="873" protocol="tcp" source address="127.0.0.1" accept'`
`firewall-cmd --reload`
This may impact legitimate remote rsync operations. If rsync is not used as a daemon, ensure that only trusted sources are used for rsync operations.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | 8.2 | 6.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | High |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | Low | Low | Low |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Red Hat CVSS v3 Score Explanation
Our rating matches the upstream. The exploitation is very complex. Hence, rating of Attack complexityL High is justified versus that of NIST which factors in AC: L
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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