CVE-2026-70453: rsyncproject rsync Inefficient Algorithmic Complexity
Vulnerability summary
CVE-2026-70453 is a high (CVSS 8.7) Inefficient Algorithmic Complexity vulnerability in rsyncproject rsync. EPSS estimates a 0.53% chance of exploitation in the next 30 days, higher than 43.3% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 12 · Related 8Timeline
- 13-08-2026PublishedVulnerability first disclosed.
- 14-08-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
8 scores · 5 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated8.7HighCVSS: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
- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated8.7HighCVSS: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
- NVDNIST8.7HighCVSS: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
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.53%
Chance of exploitation in the next 30 days
Percentile
43%
Versus all other CVEs
30-day change
0.00 pp
From 0.53% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Alpine1 product
- rsync< 3.5.0-r0
Debian1 product
- rsyncAll versions (No fix recorded) | < 3.5.0+ds1-0+deb13u1 | < 3.5.0+ds1-1
Rsyncproject1 product
- rsync≤ 3.4.4
Ubuntu1 product
- rsyncAll versions (No fix recorded)
4 vendors · 4 products
References
9 links- github.com/RsyncProject/rsync/releases/tag/v3.5.0Release Notes
- www.vulncheck.com/advisories/rsync-algorithmic-complexity-dos-via-hash-searchThird Party Advisory
