dbcve.org
Integer OverflowWeakness · CWE-190

CVE-2026-44508

HIGH · 8.1 CVSS v3.1 Published 2026-07-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
Remotely reachable Zero-click 4 weeks old

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 is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files. In versions prior to 3.4.3, the receiver's compressed-token decoder accumulated a 32-bit signed counter without checking for overflow. A malicious sender can trigger an overflow that with careful manipulation can lead to the extraction of data stored in memory of the process allowing an attacker to access environment variables, passwords and memory pointers from the heap, stack, and libraries. The leakage of these pointers and data can significantly reduce the effectiveness of ASLR and facilitate further exploitation. This issue is fixed in version 3.4.3.

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 prior to 3.4.3 contain an integer overflow vulnerability in the receiver's compressed-token decoder where a 32-bit signed counter accumulates without overflow validation. A malicious sender can trigger this overflow to read arbitrary process memory, exposing environment variables, passwords, and memory pointers from heap, stack, and libraries, significantly weakening ASLR and enabling further exploitation.

MitigationUpgrade rsync to version 3.4.3 or later to patch the integer overflow. Until patching is complete, restrict rsync connections to trusted sources and consider using SSH tunnels or VPN for additional isolation.

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

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
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

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

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' or check your package manager (dpkg -l rsync, rpm -q rsync, etc.)
    Affected if Version is lower than 3.4.3 (e.g., 3.4.2, 3.4.1, 3.4.0, 3.3.0, etc.)
  2. Confirm rsync daemon or server mode availability
    Check if rsyncd is enabled: look for /etc/rsyncd.conf, check for rsync daemon processes ('ps aux | grep rsync'), or check port 873 listeners ('netstat -tlnp | grep 873' or 'ss -tlnp | grep 873')
    Affected if Rsync daemon is configured or running, especially if accepting connections from untrusted networks
  3. Verify rsync usage for receiving data
    Review cron jobs, scripts, or automation that invoke rsync with receiver role (e.g., rsync server://..., or rsync pulling from remote hosts)
    Affected if System uses rsync to receive data from remote senders, particularly over network connections
  4. Check for exposed rsync interfaces
    Inspect firewall rules ('iptables -L' or 'ufw status'), network exposure of port 873, and any rsync modules marked 'read only = no'
    Affected if Rsync port 873 is open to untrusted networks or the internet

A system is affected if rsync version is prior to 3.4.3 AND the system acts as a receiver (runs rsyncd or uses rsync to pull data from remote sources), particularly if exposed to untrusted networks.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade rsync to version 3.4.3 or later to patch the integer overflow. Until patching is complete, restrict rsync connections to trusted sources and consider using SSH tunnels or VPN for additional isolation.

Recommended fix High confidence

3.4.3

  1. Identify the current Rsync version installed on the system using 'rsync --version' or 'rsync -V'
  2. Upgrade Rsync to version 3.4.3 or later using the package manager appropriate for your system (e.g., apt, yum, dnf, brew, or compile from source)
  3. For Debian/Ubuntu: 'sudo apt update && sudo apt install rsync'
  4. For RHEL/CentOS/Fedora: 'sudo dnf update rsync'
  5. For macOS with Homebrew: 'brew upgrade rsync'
  6. Alternatively, compile from source: download from rsync.samba.org, extract, run './configure', 'make', 'sudo make install'
  7. Verify the upgrade was successful by running 'rsync --version' and confirming the version is 3.4.3 or higher
  8. If using rsync in a server/client mode, ensure both the client and server instances are updated to prevent exploitation
Caveat Review the Rsync 3.4.3 release notes for any configuration or behavior changes; generally minor point releases have minimal breaking changes

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

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-44508 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2026-44508 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data