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CentOS Linux 8.4 [TuxCare] Security Update: rsync / rsync-daemon Multiple Vulnerabilities (CENTOS8.4:CLSA-2026:1793450567)

critical Nessus Plugin ID 374557

Synopsis

The CentOS Linux host is missing one or more security updates.

Description

The CentOS Linux 8.4 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare CENTOS8.4:CLSA-2026:1793450567 advisory.

 - rsync before 3.5.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability in the rrsync restricted shell wrapper that allows authenticated clients to escape enforced directory restrictions by substituting a symlink for a path component after validation but before transfer processing. Attackers can additionally leverage unrestricted flags such as --copy-unsafe-links, -D, and
 --log-file through rrsync to read or write files outside the permitted directory subtree. (CVE-2026-53783)

 - rsync before 3.5.0 contains multiple command and argument injection vulnerabilities that allow attackers to execute arbitrary commands by supplying malicious input through several code paths, including the RSYNC_CONNECT_PROG environment variable, daemon hooks, the rsync-ssl wrapper, and remote-shell command newline injection. Attackers can inject shell metacharacters or newline characters into unsanitized user- supplied values such as hostnames and hostspecs to execute arbitrary commands under the privileges of the rsync process or the invoking user. (CVE-2026-53790)

 - rsync before 3.5.0 contains an algorithmic complexity vulnerability in the hash_search() function that allows a remote attacker to cause a denial of service by delivering a carefully constructed file list. A sender can exploit the quadratic-time worst-case behavior in hash lookups to exhaust receiver CPU resources with a modest number of crafted entries, causing a sustained denial of service. (CVE-2026-70453)

 - rsync 3.0.0 before 3.5.0 contains an out-of-bounds write vulnerability that allows attackers to corrupt memory by triggering HLINK_BUMP processing on file entries with the FLAG_HLINKED flag set while the hard- link preservation option is inactive. Attackers can exploit the missing F_SUM field in the file_struct layout to access memory past the end of the allocated structure, corrupting adjacent heap or stack data.
 (CVE-2026-70458)

 - rsync 3.1.0 before 3.5.0 contains a signed integer overflow vulnerability in the I/O timeout implementation that allows attackers to permanently disable connection timeouts by injecting MSG_IO_TIMEOUT messages carrying non-positive (zero or negative) values. Attackers can craft malicious MSG_IO_TIMEOUT messages that cause the timeout variable to wrap to a non-positive value, preventing the timeout check from firing and enabling idle or stalled connections to hold daemon slots indefinitely, leading to resource exhaustion. (CVE-2026-70462)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages based on the guidance in TuxCare advisory CENTOS8.4:CLSA-2026:1793450567.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1793450567

http://www.nessus.org/u?deb40451

Plugin Details

Severity: Critical

ID: 374557

File Name: tuxcare_centos_8.4_CLSA-2026-1793450567.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 10/31/2026

Updated: 10/31/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.18

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 6.7

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-53790

CVSS v3

Risk Factor: High

Base Score: 8.2

Temporal Score: 7.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS Score Source: CVE-2026-70458

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 7.2

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/CentOS/release, Host/CentOS/rpm-list, Host/OS/extended-third-party

Exploit Ease: No known exploits are available

Patch Publication Date: 10/31/2026

Vulnerability Publication Date: 8/13/2026

Reference Information

CVE: CVE-2026-53783, CVE-2026-53790, CVE-2026-70453, CVE-2026-70458, CVE-2026-70462, CVE-2026-70464

CLSA: 2026:1793450567