CVE-2026-53792
Received Received - Intake

Out-of-Bounds Read in rsync Before 3.5.0

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: VulnCheck

Description
rsync before 3.5.0 contains an out-of-bounds read vulnerability in the sender-side block matching logic that allows a malicious receiver to trigger memory access before the start of an allocated buffer by sending a crafted checksum block with a length of zero. Attackers can send a specially crafted checksum set containing a zero-length block to cause a negative offset calculation during delta computation, resulting in an out-of-bounds read of file data buffer memory on the sender side.

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Meta Information

Published
2026-08-13
Last Modified
2026-08-13
Generated
2026-08-13
AI Q&A
2026-08-13
EPSS Evaluated
N/A
NVD
CVE-2026-53792
EUVD
EUVD-2026-58100

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.
CWE-129 The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

Attack-Flow Graph

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Executive Summary

This vulnerability affects rsync versions before 3.5.0. A malicious receiver can send a crafted checksum block with zero length, causing the sender to calculate a negative offset during delta computation. This leads to an out-of-bounds read, where the sender may access memory before the start of an allocated buffer, potentially exposing sensitive file data.

Detection Guidance

To detect this vulnerability, check the installed rsync version on your system using the command: rsync --version. If the version is 3.4.3 or earlier, the system is vulnerable. Additionally, monitor network traffic for rsync connections with unusual checksum blocks or malformed data packets.

Impact Analysis

An attacker could exploit this to read sensitive file data on the sender's system. The impact includes potential data leakage, system instability, or crashes due to memory corruption. The attack requires network access and user interaction but no special privileges.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, violating confidentiality requirements in GDPR and HIPAA. Organizations using vulnerable rsync versions may face compliance violations, legal penalties, and reputational damage if sensitive data is leaked.

Mitigation Strategies

Immediately update rsync to version 3.5.0 or later. If updating is not possible, restrict network access to rsync services and disable rsync daemon mode if not required. Implement network-level controls to block suspicious checksum blocks.

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