CVE-2026-70454

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TLS Certificate Validation Bypass in Rsync

Publication date: 2026-08-13

Last updated on: 2026-10-24

Assigner: VulnCheck

Description

rsync 3.2.0 through 3.2.3 (openssl mode) and rsync-ssl through 3.4.4 (stunnel mode) contain a TLS certificate validation vulnerability that allows on-path attackers to intercept encrypted sessions by presenting self-signed or otherwise invalid certificates. Attackers can exploit the failure to validate server TLS certificates against a trusted CA or verify certificate hostname matching to decrypt or tamper with rsync session content without detection by the client.

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Meta Information

Published

2026-08-13

Last Modified

2026-10-24

Generated

2026-11-08

AI Q&A

2026-08-13

EPSS Evaluated

2026-11-07

NVD

CVE-2026-70454

EUVD

EUVD-2026-58050

Affected Vendors & Products

Vendor	Product	Version / Range
rsync	rsync	From 3.2.0 (inc) to 3.2.3 (inc)
rsync	rsync	to 3.4.4 (inc)
rsync	rsync	3.5.0
rsync	rsync-ssl	to 3.4.4 (inc)
rsync	rsync_ssl	to 3.4.4 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-295	The product does not validate, or incorrectly validates, a certificate.

Attack-Flow Graph

Executive Summary

This vulnerability affects rsync versions 3.2.0 through 3.2.3 (OpenSSL mode) and rsync-ssl through 3.4.4 (stunnel mode). It involves improper TLS certificate validation, allowing attackers to intercept encrypted rsync sessions by presenting invalid or self-signed certificates. The software fails to verify certificates against trusted Certificate Authorities or check hostname matching, enabling man-in-the-middle attacks to decrypt or alter session content without detection.

Detection Guidance

Check rsync and rsync-ssl versions for vulnerability. For rsync, run 'rsync --version' and verify if it's below 3.5.0. For rsync-ssl, check the version of the wrapper script. Monitor network traffic for unexpected TLS handshakes or certificate errors during rsync sessions.

Impact Analysis

If you use vulnerable rsync versions, attackers could intercept and decrypt your rsync sessions, exposing sensitive data being transferred. They could also alter the data without your knowledge, leading to potential data tampering or corruption. This affects confidentiality and integrity of transferred files.

Compliance Impact

This vulnerability could lead to unauthorized access or tampering with sensitive data during transfer, violating GDPR's data integrity and confidentiality requirements or HIPAA's security rules for protected health information. Non-compliance risks include legal penalties, reputational damage, and loss of trust.

Mitigation Strategies

Upgrade rsync to version 3.5.0 or later. For rsync-ssl, ensure proper CA verification is configured or switch to a supported rsync version. Disable rsync-ssl if not required. Review and update TLS configuration to enforce certificate validation.

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