CVE-2026-70453

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 4.0

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

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 44% of CVEs (scores of 2026-10-25)

CWE

CWE-407

Published

2026-08-13

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

References

• https://github.com/RsyncProject/rsync/releases/tag/v3.5.0
• https://github.com/RsyncProject/rsync/security/advisories/GHSA-8x5r-mjx8-83hv
• https://www.vulncheck.com/advisories/rsync-algorithmic-complexity-dos-via-hash-search

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