Vulnerability · Published Aug 13, 2026 · Assigned by VulnCheck
CVE-2026-70453rsync < 3.5.0 Algorithmic Complexity DoS via hash_search()
High 7.5
In plain English
A high-severity security flaw in rsync from RsyncProject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | rsync | 3.5.0-3.el10_2 | ALSA-2026:67463 |
| AlmaLinux:8 | rsync | 3.1.3-28.el8_10 | ALSA-2026:74095 |
| AlmaLinux:9 | rsync | 3.2.7-1.el9_8 | ALSA-2026:67462 |
| AlmaLinux:10 | rsync-daemon | 3.5.0-3.el10_2 | ALSA-2026:67463 |
| AlmaLinux:8 | rsync-daemon | 3.1.3-28.el8_10 | ALSA-2026:74095 |
| AlmaLinux:9 | rsync-daemon | 3.2.7-1.el9_8 | ALSA-2026:67462 |
| AlmaLinux:10 | rsync-rrsync | 3.5.0-3.el10_2 | ALSA-2026:67463 |
| AlmaLinux:9 | rsync-rrsync | 3.2.7-1.el9_8 | ALSA-2026:67462 |
| Alpine:v3.21 | rsync | 3.5.0-r0 | ALPINE-CVE-2026-70453 |
| Alpine:v3.22 | rsync | 3.5.0-r0 | ALPINE-CVE-2026-70453 |
| Alpine:v3.23 | rsync | 3.5.0-r0 | ALPINE-CVE-2026-70453 |
| Alpine:v3.24 | rsync | 3.5.0-r0 | ALPINE-CVE-2026-70453 |
| Debian:12 | rsync | no fix listed | DEBIAN-CVE-2026-70453 |
| Debian:13 | rsync | 3.5.0+ds1-0+deb13u1 | DEBIAN-CVE-2026-70453 |
| Debian:14 | rsync | 3.5.0+ds1-1 | DEBIAN-CVE-2026-70453 |
| Rocky Linux:10 | rsync | 0:3.5.0-3.el10_2 | RLSA-2026:67463 |
| Rocky Linux:8 | rsync | 0:3.1.3-28.el8_10 | RLSA-2026:74095 |
| Rocky Linux:9 | rsync | 0:3.2.7-1.el9_8 | RLSA-2026:67462 |
| Ubuntu:22.04:LTS | rsync | no fix listed | UBUNTU-CVE-2026-70453 |
| Ubuntu:24.04:LTS | rsync | no fix listed | UBUNTU-CVE-2026-70453 |
| Ubuntu:26.04:LTS | rsync | no fix listed | UBUNTU-CVE-2026-70453 |
| Ubuntu:26.10 | rsync | no fix listed | UBUNTU-CVE-2026-70453 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| RsyncProject | rsync | 0 – through 3.4.4 |
Weakness: CWE-407 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- GitHub Security Advisory (GHSA-8x5r-mjx8-83hv) vendor-advisory
- rsync 3.5.0 Release Notes release-notes
- https://www.vulncheck.com/advisories/rsync-algorithmic-complexity-dos-via-hash-search third-party-advisory