Inefficient Algorithmic Complexity in Rsync - CVE-2026-70453

Vulnerability identifier: #VU142267

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-70453

CWE-ID: CWE-407

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to inefficient algorithmic complexity in hash_search() when processing a crafted checksum set containing a long chain of equal weak checksums. A remote attacker can send a specially crafted checksum set to cause a denial of service.

Sustained CPU consumption can persist as shared host resource exhaustion rather than being limited to the attacker's own transfer.

Rsync
Debian Linux
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Basesystem Module
openSUSE Leap
openEuler
Fedora
rsync-debugsource
rsync-debuginfo
rsync
rsync-help
rsync (Debian package)
rsync (Red Hat package)

Install security update from vendor's website.

Rsync - update to 3.5.0
rsync-debugsource - addressed in versions 3.2.3-150400.3.34.1, 3.2.7-150600.3.24.1
rsync-debuginfo - addressed in versions 3.2.3-150400.3.34.1, 3.2.7-150600.3.24.1
rsync - addressed in versions 3.2.3-150400.3.34.1, 3.2.7-150600.3.24.1
rsync-help - update to 3.2.7-12
rsync-debugsource - update to 3.2.7-12
rsync-debuginfo - update to 3.2.7-12
rsync - update to 3.2.7-12
rsync (Debian package) - update to 3.5.0+ds1-0+deb13u1
rsync - addressed in versions 3.5.0-1.fc43, 3.5.0-1.fc44
rsync (Red Hat package) - update to 3.5.0-3.el10_2

• https://github.com/RsyncProject/rsync/security/advisories/GHSA-8x5r-mjx8-83hv

• Multiple vulnerabilities in Rsync
• SUSE update for rsync
• Fedora 44 update for rsync
• Fedora 43 update for rsync
• SUSE update for rsync
• openEuler 24.03 LTS SP3 update for rsync
• openEuler 24.03 LTS SP1 update for rsync
• Red Hat Enterprise Linux 10 update for rsync
• openEuler 24.03 LTS SP4 update for rsync
• Debian update for rsync