Critical 9.1Published Aug 13, 2026

CVE-2026-53791rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header

Updated under an hour ago (2026-10-19 13:50 UTC)

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It affects RsyncProject rsync and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for RsyncProject rsync

Exploited in the last 30 days

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.

CVSS: 9.1 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-290
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Analyzed
Record last updated: Aug 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

RsyncProject rsync rsyncproject:rsync (from the name)	through 3.4.4; 3.5.0 not affected	CNA record
samba rsync samba:rsync	before 3.5.0	NVD

References

https://github.com/RsyncProject/rsync/security/advisories/GHSA-h2q9-5fr8-w635vendor-advisory
https://github.com/RsyncProject/rsync/releases/tag/v3.5.0release-notes, product
https://www.vulncheck.com/advisories/rsync-daemon-ip-spoofing-via-proxy-protocol-headerthird-party-advisory, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.