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RsyncApplication · Samba

CVE-2026-43619

MEDIUM · 6.3 CVSS v3.1 Published 2026-05-20
Fix available
A fix is available. Upgrade to after 3.4.2 or later.
See remediation →
65/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Rsync version 3.4.2 and prior contain symlink race condition vulnerabilities in path-based system calls including chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat that allow local attackers to redirect operations to files outside the exported rsync module. Attackers with local filesystem access can exploit the timing window between path resolution and syscall execution by swapping symlinks to apply sender-supplied permissions, ownership, timestamps, or filenames to arbitrary files outside the intended module boundary on rsync daemons configured with 'use chroot = no'.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Rsync versions 3.4.2 and prior suffer from TOCTOU (time-of-check to time-of-use) symlink race conditions in multiple path-based syscalls (chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, lstat). Local attackers with filesystem access can swap symlinks during the window between path resolution and syscall execution to redirect file operations outside the intended rsync module boundary, allowing arbitrary permission, ownership, timestamp, or filename manipulation on systems running rsync daemons with 'use chroot = no'.

MitigationEnable 'use chroot = yes' in rsync daemon configuration to constrain filesystem access, or upgrade to a patched rsync version when available. Additionally, limit local filesystem access permissions to prevent symlink manipulation by untrusted users.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RsyncApplication
Affected:<= 3.4.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed rsync version
    Run 'rsync --version' and examine the output for the version number (e.g., 'rsync version 3.4.2' or lower)
    Affected if The version displayed is 3.4.2 or any version prior to 3.4.2
  2. Confirm rsync daemon mode is in use
    Check for running rsync daemon process: 'ps aux | grep rsyncd' or look for rsyncd.conf configuration file typically located at /etc/rsyncd.conf or /etc/rsync/rsyncd.conf
    Affected if rsync is running as a daemon (rsyncd) and accepts connections from clients
  3. Locate rsyncd.conf configuration
    Search for rsyncd.conf in common locations: /etc/rsyncd.conf, /etc/rsync/rsyncd.conf, or check the path specified by 'rsync --daemon --config=/path/to/rsyncd.conf'
    Affected if An rsyncd.conf file exists and is being used to run the rsync daemon
  4. Check use chroot setting in rsyncd.conf
    Open the rsyncd.conf file and search for 'use chroot' directive within any [module] section or global section. Run 'grep -i "use chroot" /path/to/rsyncd.conf' to find the setting
    Affected if The 'use chroot' directive is set to 'no' or is absent (default is often 'yes' in some versions, but verify explicitly)
  5. Verify module path boundaries
    Examine each module section in rsyncd.conf (lines starting with [modulename]) and check the 'path' directive to identify what directories are being exported
    Affected if Modules export paths that contain or link to sensitive directories outside the intended module boundary

You are affected if running rsync 3.4.2 or prior as a daemon with 'use chroot = no' or missing the chroot directive, allowing symlink race conditions to escape module boundaries.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 3.4.2
Interim mitigation

Enable 'use chroot = yes' in rsync daemon configuration to constrain filesystem access, or upgrade to a patched rsync version when available. Additionally, limit local filesystem access permissions to prevent symlink manipulation by untrusted users.

Recommended fix Moderate confidence

Rsync 3.4.3 or later stable release

  1. 1. Check current Rsync version by running: rsync --version
  2. 2. Identify the package manager used (apt, yum, dnf, brew, etc.)
  3. 3. For Debian/Ubuntu: Run 'sudo apt update && sudo apt install rsync' to get the latest available version
  4. 4. For RHEL/CentOS/Fedora: Run 'sudo dnf update rsync' or 'sudo yum update rsync'
  5. 5. For macOS with Homebrew: Run 'brew upgrade rsync'
  6. 6. Alternatively, download latest Rsync source from rsync.samba.org and compile: git clone https://github.com/RsyncProject/rsync.git && cd rsync && ./configure && make && sudo make install
  7. 7. Verify the new version is installed: rsync --version
  8. 8. If running as a daemon (rsyncd), ensure configuration file (/etc/rsyncd.conf) sets 'use chroot = yes' as a defense-in-depth measure
Caveat Minor: If upgrading from significantly older versions, review release notes for any deprecated options; the use chroot=yes setting may change some daemon path behaviors

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Rsync Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-43619 in production — separate from our analysis above.

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