by Kastro
Paper/Archive/CVE-2026-53791

CVE-2026-53791

RsyncProject rsync — rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header

EPSS 0.5%CVSS 9.1
critical.is priorityof 100
36
CVSS 9.1 (CNA)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 42.9.429 × 208.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.

Affected

ProductAffectedFixed inSource
rsync≤ 3.4.43.5.0CNA

Scores by source

VulnCheck (CNA)9.1CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
VulnCheck (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial

References

advisorygithub.com/RsyncProject/rsync/security/advisories/GHSA-h2q9-5fr8-w635refgithub.com/RsyncProject/rsync/releases/tag/v3.5.0writeupvulncheck.com/advisories/rsync-daemon-ip-spoofing-via-proxy-protocol-header