rsync 3.1.0 before 3.5.0 contains an access control bypass vulnerability that allows remote attackers to circumvent hosts deny rules by inducing DNS resolution failures during hostname-based access control evaluation. When a DNS lookup for a hostname-based deny rule fails, the daemon skips the rule rather than defaulting to a deny decision, enabling attackers who can trigger DNS failures to bypass module-level IP access controls and gain unauthorized access to restricted module file trees.
CVSS Details
- CVSS 4.0 Base Score: 9.1 (CRITICAL)
- CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:H/AT:N/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)
- CVSS 3.1 Base Score: 7.4
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade rsync | Sep 1, 2026 | Aug 13, 2026 |
| Freebsd | — | Upgrade rsync | Aug 27, 2026 | Aug 25, 2026 |
| Redhat_linux | — | No solution existsUpgrade rsync-rrsyncUpgrade rsync-debuginfoUpgrade rsync-daemonUpgrade rsync-debugsourceUpgrade rsync | Aug 24, 2026 | Aug 13, 2026 |
| Rocky_linux | — | Upgrade rsyncUpgrade rsync-debuginfoUpgrade rsync-debugsource | Sep 17, 2026 | Sep 15, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Sep 15, 2026 | Aug 13, 2026 |
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