{"id":"CVE-2026-44507","summary":"Rsync: hostname/ACL bypass on DNS-lookup failure","details":"Rsync is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files.  In versions prior to 3.4.3, when using a daemon configured with a chroot, the reverse DNS lookup of the connecting client was performed after the chroot had been entered. If the chroot did not contain the files glibc needs for resolution (/etc/resolv.conf, /etc/nsswitch.conf,\n/etc/hosts, NSS service modules), the lookup failed and the connecting hostname was set to \"UNKNOWN\". Hostname-based deny rules (\"hosts deny = *.evil.example\") therefore could not match, and an attacker who controlled the PTR record for their source IP could connect from a hostname that the administrator had intended to deny. IP-based ACLs (\"hosts allow = 10.0.0.0/8\") are unaffected. This issue is fixed in version 3.4.3.","aliases":["CVE-2026-43617","GHSA-rjfm-3w2m-jf4f"],"modified":"2026-07-23T03:42:40.085504413Z","published":"2026-07-20T20:29:26.577Z","database_specific":{"cwe_ids":["CWE-863"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44507.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44507.json"},{"type":"ADVISORY","url":"https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjfm-3w2m-jf4f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44507"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/rsyncproject/rsync","events":[{"introduced":"0"},{"fixed":"2c7777aaa62abeb1bca192da345e6e8c685e872a"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.4.3"}],"source":"AFFECTED_FIELD"}}],"versions":["v3.2.7","v3.4.1","v3.4.2","v3.4.0","v3.3.0","v3.3.0pre1","v3.2.7pre1","v3.2.6","v3.2.5","v3.2.5pre2","v3.2.5pre1","v3.2.4","v3.2.4pre4","v3.2.4pre3","v3.2.4pre2","v3.2.4pre1","v3.2.3","v3.2.3pre1","v3.2.2","v3.2.2pre3","v3.2.2pre2","v3.2.2pre1","v3.2.1","v3.2.1pre1","v3.2.0","v3.2.0pre3","v3.2.0pre2","v3.2.0pre1","v3.1.3","v3.1.3pre1","v3.1.2","v3.1.2pre1","v3.1.1","v3.1.1pre2","v3.1.1pre1","v3.1.0","v3.1.0pre1","v3.0.3","v3.0.3pre3","v3.0.3pre2","v3.0.3pre1","v3.0.2","v3.0.1","v3.0.1pre3","v3.0.1pre2","v3.0.1pre1","v3.0.0","v3.0.0pre10","v3.0.0pre9","v3.0.0pre8","v3.0.0pre7","v3.0.0pre6","v3.0.0pre5","v3.0.0pre4","v3.0.0pre3","v3.0.0pre2","v3.0.0pre1","v2.6.9","v2.6.9pre3","v2.6.9pre2","v2.6.9pre1","v2.6.8","v2.6.8pre1","v2.6.7","v2.6.7pre3","v2.6.7pre2","v2.6.7pre1","v2.6.6pre1","v2.6.5","v2.6.5pre2","v2.6.5pre1","v2.6.4","v2.6.4pre4","v2.6.4pre3","v2.6.4pre2","v2.6.4pre1","v2.6.3","v2.6.3pre2","v2.6.3pre1","v2.6.2","v2.6.2pre1","v2.6.1","v2.6.1pre2","v2.6.1pre1","v2.6.0","v2.6.0pre2","v2.6.0pre1","v2.5.6","v2.5.5","v2.5.5.rc1","v2.5.4","v2.5.4pre1","v2.5.3","v2.5.3pre1","v2.5.2","v2.5.2pre3","v2.5.2pre2","v2.5.2pre1","v2.5.1","v2.5.1pre3","v2.5.1pre2","v2.5.1pre1","v2.5.0","v2.4.7pre4","v2.4.7pre2","mbp_bk_export0","v2.4.6","v2.4.5","v2.4.4","v2.4.3","v2.4.2","v2.4.1","v2.4.0","v2.3.2","v2.3.1","v2.3.0","v2.2.1","v2.2.0","v2.1.1","v2.1.0","v2.0.19","v2.0.18","v2.0.17","v2.0.16","v2.0.15","v2.0.14","v2.0.13","v2.0.12","v2.0.11","v2.0.10","v2.0.9","v2.0.8","v2.0.7","v2.0.6","v2.0.5","v2.0.4","v2.0.3","v2.0.2","v2.0.1","v2.0.0","v1.7.4","v1.7.3","v1.7.2","v1.7.1","v1.7.0","v1.6.9","v1.6.8","v1.6.7","v1.6.6","v1.6.5","v1.6.4"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-44507.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}