rsync 3.1.0 < 3.5.0 Authorization Bypass via auth users Directive Parsing
Noroxi assessment
Priority: Monitor (action score 34/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.36% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. 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 3.1.0 before 3.5.0 contains an authorization bypass in auth users directive parsing. The auth users parser uses comma-only tokenization when splitting the user list, which fails to correctly handle entries of the form @Group Name where the group name contains a space. The space within the group name causes the parser to split the entry at the space boundary, discarding the deny rule associated with the group. An authenticated user whose username or group membership would be denied by an @Group Name auth users entry can connect to a restricted module because the deny rule is silently discarded during parsing.
- Published
- Aug 13, 2026
- Updated
- Aug 31, 2026
- EPSS
- 0.3% · 28th percentile
- CWE
- CWE-863
Report tools
Action score
34
Monitor
Low priority for now.
- CVSS
- 34 / 40 · 8.6 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 8.6
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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
- Proof of concept exists, no weaponized module
- 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 rsync3.1.0 and later · before 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
- 3.1.0 and later · 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:8 | rsync | before 3.1.3-28.el8_10 | 3.1.3-28.el8_10 |
| AlmaLinux:8 | rsync-daemon | before 3.1.3-28.el8_10 | 3.1.3-28.el8_10 |
| 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 | from 3.1.0 · before 3.5.0-r0 | 3.5.0-r0 |
| Debian:12 | rsync | all versions | — |
| 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 |
| 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:8::baseos | rsync | before 0:3.1.3-28.el8_10 | 0:3.1.3-28.el8_10 |
| Red Hat:enterprise_linux:8::baseos | rsync-daemon | before 0:3.1.3-28.el8_10 | 0:3.1.3-28.el8_10 |
| Red Hat:enterprise_linux:8::baseos | rsync-debuginfo | before 0:3.1.3-28.el8_10 | 0:3.1.3-28.el8_10 |
| Red Hat:enterprise_linux:8::baseos | rsync-debugsource | before 0:3.1.3-28.el8_10 | 0:3.1.3-28.el8_10 |
| 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 |
+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
- CVE-2017-15994rsync 3.1.3-development before 2017-10-24 mishandles archaic checksums, which makes it easier for remote attackers to bypass intended access39Monitor
- CVE-2026-53791rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header36Monitor
- CVE-2026-70461rsync 3.2.5 < 3.5.0 Heap Out-of-Bounds Write via files-from Entry35Monitor
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) |
| 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) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:0 | 2026-08-28 |
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.
- Published
- First PoC+15 d
- TodayOct 16, 2026+64 d
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.
- 4drezfinder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-537860 days apartrsync < 3.5.0 Filter Rule Bypass via --filter Merge Directive27Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
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.
- A low-privileged account is enough.
- 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
- Low
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-863 · Incorrect AuthorizationCVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
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References
Show all references (2 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.