Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-reachable with no auth or complexity prerequisites; impact is CPU exhaustion on the receiver (availability only); no confidentiality or integrity impact; scope unchanged as only the receiver process is affected.
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
CPU exhaustion in rsync receivers before 3.5.0 allows a remote sender to cause denial of service by exploiting quadratic-time worst-case behavior in the hash_search() function (CWE-407). A malicious or compromised sender delivers a carefully crafted file list - requiring only a modest number of entries - to collapse hash lookup performance and sustain receiver CPU exhaustion for the duration of the sync session. No public exploit has been identified at time of analysis, but the unauthenticated network attack vector and rsync's ubiquitous deployment in backup and file-synchronization infrastructure make patch urgency high.
Technical ContextAI
rsync implements a delta-transfer algorithm that relies on rolling checksums and hash tables to match file blocks between sender and receiver. The affected component, hash_search(), performs hash-based lookups over file list entries during the matching phase. CWE-407 (Insufficient Algorithmic Complexity) describes flaws where an algorithm degrades from expected O(n) to O(n²) or worse under adversarially chosen input - typically via hash collision chains that force linear probing through the entire table for every lookup. A sender controlling the file list content can select entry names or metadata that produce worst-case hash collisions in the receiver's table, turning a normally fast operation into a CPU-intensive traversal. The CPE cpe:2.3:a:rsyncproject:rsync:*:*:*:*:*:*:*:* covers all versions prior to 3.5.0 across all platforms. The attack is protocol-native: no out-of-band channel or memory corruption is required - only valid rsync protocol messages with crafted content.
RemediationAI
Upgrade rsync to version 3.5.0 or later; this is the vendor-released patch confirmed by the RsyncProject GitHub release tag and security advisory GHSA-8x5r-mjx8-83hv (https://github.com/RsyncProject/rsync/releases/tag/v3.5.0). If immediate upgrade is not feasible, restrict rsync receiver access to known, trusted sender IP addresses using firewall ACLs or the hosts allow directive in rsyncd.conf - this reduces the attacker pool but does not eliminate risk from compromised trusted hosts and requires accurate IP allowlisting. Rate-limiting incoming rsync connections at the network perimeter (e.g., iptables connlimit or fail2ban) raises the cost of sustaining the DoS but does not prevent a single malicious session from exhausting CPU during its lifetime. Running the rsync receiver process with reduced scheduling priority (nice +10 or systemd CPUWeight) limits collateral damage to co-located services but does not prevent the DoS itself. None of these workarounds address the root cause - patching to 3.5.0 is the only definitive fix.
A flaw was found in rsync which could be triggered when rsync compares file checksums. Rated high severity (CVSS 7.5), t
A heap-based buffer overflow flaw was found in the rsync daemon. Rated critical severity (CVSS 9.8), this vulnerability
rsync 3.1.1 allows remote attackers to write to arbitrary files via a symlink attack on a file in the synchronization pa
Server-to-client path traversal in rsync lets a malicious or compromised rsync server write files outside the client's i
An issue was discovered in rsync before 3.2.5 that allows malicious remote servers to write arbitrary files inside the d
The check_secret function in authenticate.c in rsync 3.1.0 and earlier allows remote attackers to cause a denial of serv
A flaw was found in rsync. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authenticati
The receive_xattr function in xattrs.c in rsync 3.1.2 and 3.1.3-development does not check for a trailing '\0' character
The daemon in rsync 3.1.2, and 3.1.3-development before 2017-12-03, does not check for fnamecmp filenames in the daemon_
rsync 3.1.3-development before 2017-10-24 mishandles archaic checksums, which makes it easier for remote attackers to by
Arbitrary command execution in rsync before 3.5.0 arises from multiple unsanitized code paths - the RSYNC_CONNECT_PROG e
Arbitrary file write in rsync 2.3.3 through 3.4.4 lets a malicious sender escape a daemon module's root by abusing symli
Same weakness CWE-407 – Inefficient Algorithmic Complexity
View allSame technique Denial Of Service
View allVendor StatusVendor
SUSE
Severity: Important| Product | Status |
|---|---|
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Micro 5.3 | Affected |
| SUSE Linux Enterprise Micro 5.4 | Affected |
| SUSE Linux Enterprise Micro 5.5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | Affected |
| SUSE Linux Enterprise Desktop 15 SP7 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected |
| SUSE Manager Proxy LTS 4.3 | Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | Affected |
| SUSE Manager Server LTS 4.3 | Affected |
| SUSE Linux Enterprise Desktop 15 SP7 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Affected |
| SUSE Linux Enterprise Micro 5.3 | Affected |
| SUSE Linux Enterprise Micro 5.4 | Affected |
| SUSE Linux Enterprise Micro 5.5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | Affected |
| SUSE Linux Enterprise Server 16.0 | Affected |
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Micro 6.0 | Affected |
| SUSE Linux Micro 6.1 | Affected |
| SUSE Linux Micro 6.2 | Affected |
| openSUSE Leap 16.0 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | Affected |
| SUSE Linux Enterprise Server 12 SP5 | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security | Affected |
| SUSE Linux Enterprise Server 15 SP4 | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP5 | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6 | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected |
| SUSE Manager Proxy 4.3 | Affected |
| SUSE Manager Proxy LTS 4.3 | Affected |
| SUSE Manager Retail Branch Server 4.3 | Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | Affected |
| SUSE Manager Server 4.3 | Affected |
| SUSE Manager Server LTS 4.3 | Affected |
| SUSE CaaS Platform 3.0 | Affected |
| SUSE CaaS Platform 4.0 | Affected |
| SUSE Enterprise Storage 6 | Affected |
| SUSE Enterprise Storage 7 | Affected |
| SUSE Enterprise Storage 7.1 | Affected |
| SUSE Linux Enterprise Desktop 12 | Affected |
| SUSE Linux Enterprise Desktop 12 SP1 | Affected |
| SUSE Linux Enterprise Desktop 12 SP2 | Affected |
| SUSE Linux Enterprise Desktop 12 SP3 | Affected |
| SUSE Linux Enterprise Desktop 12 SP4 | Affected |
| SUSE Linux Enterprise Desktop 15 | Affected |
| SUSE Linux Enterprise Desktop 15 SP1 | Affected |
| SUSE Linux Enterprise Desktop 15 SP2 | Affected |
| SUSE Linux Enterprise Desktop 15 SP3 | Affected |
| SUSE Linux Enterprise Desktop 15 SP4 | Affected |
| SUSE Linux Enterprise Desktop 15 SP5 | Affected |
| SUSE Linux Enterprise Desktop 15 SP6 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP2 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP3 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP4 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | Affected |
| SUSE Linux Enterprise High Performance Computing 15-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15-LTSS | Affected |
| SUSE Linux Enterprise Micro 5.0 | Affected |
| SUSE Linux Enterprise Micro 5.1 | Affected |
| SUSE Linux Enterprise Micro 5.2 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | Affected |
| SUSE Linux Enterprise Point of Sale 12 SP2-CLIENT | Affected |
| SUSE Linux Enterprise Real Time 15 SP2 | Affected |
| SUSE Linux Enterprise Real Time 15 SP3 | Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | Affected |
| SUSE Linux Enterprise Server 12 | Affected |
| SUSE Linux Enterprise Server 12 SP1 | Affected |
| SUSE Linux Enterprise Server 12 SP1-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP2 | Affected |
| SUSE Linux Enterprise Server 12 SP2-BCL | Affected |
| SUSE Linux Enterprise Server 12 SP2-ESPOS | Affected |
| SUSE Linux Enterprise Server 12 SP2-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP3 | Affected |
| SUSE Linux Enterprise Server 12 SP3-BCL | Affected |
| SUSE Linux Enterprise Server 12 SP3-ESPOS | Affected |
| SUSE Linux Enterprise Server 12 SP3-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP4 | Affected |
| SUSE Linux Enterprise Server 12 SP4-ESPOS | Affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 12-LTSS | Affected |
| SUSE Linux Enterprise Server 15 | Affected |
| SUSE Linux Enterprise Server 15 SP1 | Affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP2 | Affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP3 | Affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise Server 15-LTSS | Affected |
| SUSE Linux Enterprise Server for Raspberry Pi 12 SP2 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Affected |
| SUSE Manager Proxy 4.0 | Affected |
| SUSE Manager Proxy 4.1 | Affected |
| SUSE Manager Proxy 4.2 | Affected |
| SUSE Manager Retail Branch Server 4.0 | Affected |
| SUSE Manager Retail Branch Server 4.1 | Affected |
| SUSE Manager Retail Branch Server 4.2 | Affected |
| SUSE Manager Server 4.0 | Affected |
| SUSE Manager Server 4.1 | Affected |
| SUSE Manager Server 4.2 | Affected |
| SUSE OpenStack Cloud 7 | Affected |
| SUSE OpenStack Cloud 8 | Affected |
| SUSE OpenStack Cloud 9 | Affected |
| SUSE OpenStack Cloud Crowbar 8 | Affected |
| SUSE OpenStack Cloud Crowbar 9 | Affected |
| openSUSE Leap 15.3 | Affected |
| openSUSE Leap 15.4 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
| openSUSE Leap Micro 5.2 | Affected |
| openSUSE Leap Micro 5.3 | Affected |
| openSUSE Leap Micro 5.4 | Affected |
| openSUSE Leap Micro 5.5 | Affected |
| bci/kiwi kiwi-templates-Minimal kiwi-templates-Minimal-Cloud-sap kiwi-templates-Minimal-MS-HyperV-sap kiwi-templates-Minimal-VMware-sap kiwi-templates-Minimal-kvm-and-xen-sap rancher/elemental-builder-image/5.3 rancher/elemental-teal-rt/5.3 rancher/elemental-teal-rt/5.4 rancher/elemental-teal/5.3 rancher/elemental-teal/5.4 rancher/seedimage-builder suse/hpc/warewulf4-x86_64/sle-hpc-node suse/manager/5.0/x86_64/server suse/multi-linux-manager/5.1/x86_64/server suse/multi-linux-manager/5.2/x86_64/server suse/sle-micro-rancher/5.2 suse/sle-micro-rancher/5.3 suse/sle-micro-rancher/5.4 suse/sle-micro/5.5 suse/sle-micro/base-5.5 suse/sle-micro/kvm-5.5 suse/sle-micro/rt-5.5 | Affected |
| suse/sles-16.1-kubevirt-minimal | Affected |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-58051