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Untriaged
Permalink CVE-2026-44507
4.8 MEDIUM
  • CVSS version (CVSS): 3.1
  • Attack Vector (AV): Network (N)
  • Attack Complexity (AC): High (H)
  • Privileges Required (PR): None (N)
  • User Interaction (UI): None (N)
  • Scope (S): Unchanged (U)
  • Confidentiality (C): Low (L)
  • Integrity (I): Low (L)
  • Availability (A): None (N)
  • Modified Attack Vector (MAV): Network (N)
  • Modified Attack Complexity (MAC): High (H)
  • Modified Privileges Required (MPR): None (N)
  • Modified User Interaction (MUI): None (N)
  • Modified Confidentiality (MC): Low (L)
  • Modified Scope (MS): Unchanged (U)
  • Modified Integrity (MI): Low (L)
  • Modified Availability (MA): None (N)
created 2 weeks, 1 day ago Activity log
  • Created suggestion 2 weeks, 1 day ago
Rsync: hostname/ACL bypass on DNS-lookup failure

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, /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.

Affected products

rsync
  • ==< 3.4.3

Matching in nixpkgs

pkgs.rsync

Fast incremental file transfer utility

pkgs.grsync

Synchronize folders, files and make backups

pkgs.rrsync

Helper to run rsync-only environments from ssh-logins

pkgs.rsyncy

Progress bar wrapper for rsync

pkgs.btrsync

Btrfs replication made easy

  • nixos-unstable 0.3
    • nixpkgs-unstable 0.3
    • nixos-unstable-small 0.3
  • nixos-26.05 0.3
    • nixos-26.05-small 0.3
    • nixpkgs-26.05-darwin 0.3

pkgs.parsync

Tool to parallel rsync-like pull sync over SSH

pkgs.librsync

Implementation of the rsync remote-delta algorithm

pkgs.diskrsync

Rsync for block devices and disk images

Package maintainers