CVE-2026-53791: rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header
Noroxi assessment
Priority: Monitor (action score 36/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.50% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: rsync (AlmaLinux:10) 3.5.0-3.el10_2; rsync-daemon (AlmaLinux:10) 3.5.0-3.el10_2; rsync-rrsync (AlmaLinux:10) 3.5.0-3.el10_2.
Low priority for now. Upgrade to rsync (AlmaLinux:10) 3.5.0-3.el10_2; rsync-daemon (AlmaLinux:10) 3.5.0-3.el10_2; rsync-rrsync (AlmaLinux:10) 3.5.0-3.el10_2 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Aug 13, 2026
- Updated
- Oct 24, 2026
- EPSS
- 0.5% · 42th percentile
- CWE
- CWE-290
Report tools
Action score
36
Monitor
Low priority for now.
- CVSS
- 36 / 40 · 9.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 9.1
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| samba | rsync | cpe:2.3:a:samba:rsync |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- samba rsyncbefore 3.5.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.
RsyncProject rsync
- 3.5.0not affected
- up to and including 3.4.4affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | rsync | before 3.5.0-3.el10_2 | 3.5.0-3.el10_2 |
| AlmaLinux:10 | rsync-daemon | before 3.5.0-3.el10_2 | 3.5.0-3.el10_2 |
| AlmaLinux:10 | rsync-rrsync | before 3.5.0-3.el10_2 | 3.5.0-3.el10_2 |
| AlmaLinux:9 | rsync | before 3.2.7-1.el9_8 | 3.2.7-1.el9_8 |
| AlmaLinux:9 | rsync-daemon | before 3.2.7-1.el9_8 | 3.2.7-1.el9_8 |
| AlmaLinux:9 | rsync-rrsync | before 3.2.7-1.el9_8 | 3.2.7-1.el9_8 |
| Alpine:v3.21 | rsync | before 3.5.0-r0 | 3.5.0-r0 |
| Debian:12 | rsync | from 0 | — |
| Debian:13 | rsync | before 3.5.0+ds1-0+deb13u1 | 3.5.0+ds1-0+deb13u1 |
| Debian:14 | rsync | before 3.5.0+ds1-1 | 3.5.0+ds1-1 |
| openSUSE:Leap 16.0 | rsync | before 3.4.1-160000.6.1 | 3.4.1-160000.6.1 |
| openSUSE:Tumbleweed | rsync | before 3.5.1-1.1 | 3.5.1-1.1 |
| Red Hat:enterprise_linux:10.2 | rsync | before 0:3.5.0-3.el10_2 | 0:3.5.0-3.el10_2 |
| Red Hat:enterprise_linux:10.2 | rsync-daemon | before 0:3.5.0-3.el10_2 | 0:3.5.0-3.el10_2 |
| Red Hat:enterprise_linux:10.2 | rsync-debuginfo | before 0:3.5.0-3.el10_2 | 0:3.5.0-3.el10_2 |
| Red Hat:enterprise_linux:10.2 | rsync-debugsource | before 0:3.5.0-3.el10_2 | 0:3.5.0-3.el10_2 |
| Red Hat:enterprise_linux:10.2 | rsync-rrsync | before 0:3.5.0-3.el10_2 | 0:3.5.0-3.el10_2 |
| Red Hat:enterprise_linux:9::appstream | rsync-daemon | before 0:3.2.7-1.el9_8 | 0:3.2.7-1.el9_8 |
| Red Hat:enterprise_linux:9::appstream | rsync-rrsync | before 0:3.2.7-1.el9_8 | 0:3.2.7-1.el9_8 |
| Red Hat:enterprise_linux:9::baseos | rsync | before 0:3.2.7-1.el9_8 | 0:3.2.7-1.el9_8 |
| Red Hat:enterprise_linux:9::baseos | rsync-debuginfo | before 0:3.2.7-1.el9_8 | 0:3.2.7-1.el9_8 |
| Red Hat:enterprise_linux:9::baseos | rsync-debugsource | before 0:3.2.7-1.el9_8 | 0:3.2.7-1.el9_8 |
| Rocky Linux:10 | rsync | before 0:3.5.0-3.el10_2 | 0:3.5.0-3.el10_2 |
| Rocky Linux:9 | rsync | before 0:3.2.7-1.el9_8 | 0:3.2.7-1.el9_8 |
+5
Same product
samba: all recordsOther highest-scoring records for the same primary product.
- CVE-2024-12084Rsync: heap buffer overflow in rsync due to improper checksum length handling61This week
- CVE-2017-16548The receive_xattr function in xattrs.c in rsync 3.1.2 and 3.1.3-development does not check for a trailing '\0' character in an xattr name, w41Plan
- CVE-2017-17434The daemon in rsync 3.1.2, and 3.1.3-development before 2017-12-03, does not check for fnamecmp filenames in the daemon_filter_list data str40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-53786Aug 13, 2026 · rsync < 3.5.0 Filter Rule Bypass via --filter Merge Directive27Monitor
- ← EarlierCVE-2026-53789Aug 13, 2026 · rsync < 3.5.0 Arbitrary File Deletion via Malicious File List28Monitor
- Later →CVE-2026-53795Aug 13, 2026 · rsync < 3.5.0 Arbitrary File Write via --temp-dir/--link-dest28Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:rsync | 3.2.7-1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:rsync-daemon | 3.2.7-1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:rsync-rrsync | 3.2.7-1.el9_8 · AlmaLinux:9 | Package registry (OSV) |
| alpine:rsync | 3.5.0-r0 · Alpine:v3.21 | Package registry (OSV) |
| debian:rsync | 3.5.0+ds1-0+deb13u1 · Debian:13 | Package registry (OSV) |
| opensuse:rsync | 3.5.1-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:rsync | 0:3.2.7-1.el9_8 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:rsync-daemon | 0:3.2.7-1.el9_8 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:rsync-debuginfo | 0:3.2.7-1.el9_8 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:rsync-debugsource | 0:3.2.7-1.el9_8 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:rsync-rrsync | 0:3.2.7-1.el9_8 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| rocky linux:rsync | 0:3.2.7-1.el9_8 · Rocky Linux:9 | Package registry (OSV) |
| suse:rsync | 3.2.7-8.1 · SUSE:Linux Micro 6.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
—
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2026-537840 days apartrsync < 3.5.0 Path Traversal via Symlink Module Root33Monitor
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-290 · Authentication Bypass by SpoofingCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Exploitation of Trusted IdentifiersCAPEC-21likelihood: High · High
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Creating a Rogue Certification Authority CertificateCAPEC-459likelihood: Medium · Very High
- Web Services API Signature Forgery Leveraging Hash Function Extension WeaknessCAPEC-461High
- Signature SpoofCAPEC-473
- Signature Spoofing by MisrepresentationCAPEC-476likelihood: Low · High
- Session Credential Falsification through PredictionCAPEC-59likelihood: High · High
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
ATT&CK techniques
- Masquerading: Invalid Code SignatureT1036.001
- Access Token ManipulationT1134
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Steal Application Access TokenT1528
- Steal Web Session CookieT1539
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Subvert Trust Controls: Code SigningT1553.002
- Adversary-in-the-MiddleT1557
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (2 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.