CVE-2026-44067: Netatalk Information Disclosure Flaw

CVE-2026-44067 Overview

CVE-2026-44067 is a heap over-read vulnerability in the extended attribute (EA) header parsing logic of Netatalk, an open-source implementation of the Apple Filing Protocol (AFP). The flaw affects Netatalk versions 2.1.0 through 4.4.2. A remote authenticated attacker can send crafted EA data to read limited adjacent heap memory or cause a minor service disruption. The vulnerability is classified under CWE-125: Out-of-Bounds Read.

Critical Impact

An authenticated remote attacker can trigger an out-of-bounds read in the Netatalk AFP server, exposing limited heap contents or interrupting file-sharing service availability.

Affected Products

• Netatalk 2.1.0 through 2.x releases
• Netatalk 3.x releases
• Netatalk 4.0.0 through 4.4.2

Discovery Timeline

• 2026-05-21 - CVE-2026-44067 published to NVD
• 2026-05-21 - Last updated in NVD database

Technical Details for CVE-2026-44067

Vulnerability Analysis

The vulnerability resides in the routine that parses extended attribute (EA) headers within Netatalk. Netatalk stores Apple-specific metadata using AppleDouble files and EA structures that include length and offset fields describing attribute entries.

When the parser processes a crafted EA header, it fails to validate that the declared sizes or offsets remain within the bounds of the allocated heap buffer. The resulting heap over-read causes the server to access memory outside the intended buffer.

Because the read occurs on a server-side heap region, an attacker may retrieve fragments of adjacent process memory or trigger a fault that disrupts the AFP daemon. The exploit requires the attacker to authenticate to the AFP service, which limits exposure to environments where credentials are available or where guest access is enabled.

Root Cause

The root cause is missing or insufficient bounds validation on length and offset fields parsed from attacker-controlled EA header data. The parser trusts attacker-supplied size values when computing pointer arithmetic into heap memory, producing an out-of-bounds read as described in CWE-125.

Attack Vector

Exploitation requires network access to a Netatalk AFP service and valid authentication credentials. The attacker submits crafted EA metadata against a shared volume that the Netatalk server then parses. High attack complexity reflects the precise structure required in the malformed EA header to trigger the over-read without prior crashes.

No verified public proof-of-concept exploit is available at the time of publication. Refer to the Netatalk Security Advisory for vendor-supplied technical details.

Detection Methods for CVE-2026-44067

Indicators of Compromise

• Unexpected crashes, restarts, or segmentation faults in the afpd or cnid_dbd Netatalk daemons recorded in system logs.
• Anomalous AFP sessions issuing repeated FPSetExtAttr or FPGetExtAttr operations from a single authenticated client.
• Sudden growth in Netatalk error logs referencing EA parsing or AppleDouble header processing.

Detection Strategies

• Monitor authenticated AFP sessions for malformed extended attribute operations and unusually large EA header values.
• Correlate process crash telemetry from hosts running Netatalk with concurrent AFP session activity to identify exploitation attempts.
• Review authentication logs for AFP service logins originating from unexpected networks or accounts not typically accessing file shares.

Monitoring Recommendations

• Enable verbose logging on afpd and forward logs to a centralized SIEM for retention and correlation.
• Alert on repeated daemon restarts within short time windows on any host exposing Netatalk to untrusted networks.
• Track network flows to TCP port 548 and restrict ingress to known administrative subnets where possible.

How to Mitigate CVE-2026-44067

Immediate Actions Required

• Upgrade Netatalk to a fixed release as identified in the Netatalk Security Advisory for CVE-2026-44067.
• Restrict AFP service exposure to trusted network segments and require strong authentication for all users.
• Audit existing AFP accounts and disable guest or anonymous access where it is not strictly required.

Patch Information

The Netatalk project has published guidance and fixed builds through the Netatalk Security Advisory. Administrators should update from any version in the 2.1.0 through 4.4.2 range to a patched release and restart the afpd daemon to apply the fix.

Workarounds

• Block inbound TCP port 548 at perimeter and host firewalls for systems that do not require external AFP access.
• Disable the Netatalk service on hosts where AFP file sharing is not required until patching is complete.
• Enforce least-privilege accounts on AFP shares to limit which users can write or modify extended attributes.

# Configuration example: restrict AFP exposure with host firewall (iptables)
iptables -A INPUT -p tcp --dport 548 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 548 -j DROP

# Stop the Netatalk daemon until a patched build is deployed
systemctl stop netatalk
systemctl disable netatalk