CVE-2026-44063: Netatalk LDAP Injection Vulnerability

CVE-2026-44063 Overview

CVE-2026-44063 is an LDAP injection vulnerability affecting Netatalk versions 2.1.0 through 4.4.2. Netatalk is an open-source implementation of the Apple Filing Protocol (AFP) used to provide file services to macOS clients from Unix-like systems. The flaw allows a remote authenticated attacker to manipulate Lightweight Directory Access Protocol (LDAP) queries through crafted filter input. Successful exploitation can result in limited information disclosure or unauthorized modification of LDAP directory entries. The weakness is tracked under [CWE-90] (Improper Neutralization of Special Elements used in an LDAP Query).

Critical Impact
An authenticated remote attacker can manipulate LDAP queries to read or alter directory entries, potentially affecting identity data used by Netatalk for authentication and authorization.

Affected Products

Netatalk 2.1.0 through 2.x releases
Netatalk 3.x releases up to 3.x final
Netatalk 4.0.0 through 4.4.2

Discovery Timeline

2026-05-21 - CVE-2026-44063 published to NVD
2026-05-21 - Last updated in NVD database

Technical Details for CVE-2026-44063

Vulnerability Analysis

The vulnerability resides in how Netatalk constructs LDAP search filters from attacker-controlled input. The application accepts filter input from an authenticated user and embeds it directly into an LDAP query without adequately escaping LDAP metacharacters such as *, (, ), \, and NUL. An attacker who supplies crafted filter values can alter the logical structure of the query. The resulting injection lets the attacker broaden search scopes, enumerate attributes outside the intended result set, or in some configurations trigger LDAP modify operations against directory entries. Exploitation requires valid credentials and a high attack complexity, which limits broad opportunistic abuse but does not eliminate insider or post-compromise risk. Impact is bounded to limited confidentiality loss and limited integrity changes, with no direct availability impact.

Root Cause

The root cause is missing or insufficient neutralization of LDAP special characters before incorporating user-supplied data into LDAP search and modification filters. Netatalk's LDAP integration code constructs filter strings via concatenation rather than using a sanitization routine compliant with RFC 4515 filter escaping. This pattern matches [CWE-90].

Attack Vector

The attack vector is network-based and requires low-privileged authentication. An attacker authenticates to a Netatalk service that performs LDAP-backed lookups, then submits filter input containing LDAP operators to influence the resulting query. The vulnerability mechanism is described in the Netatalk Security Advisory. No public proof-of-concept exploit code is available at this time.

Detection Methods for CVE-2026-44063

Indicators of Compromise

LDAP server logs containing search filters with unexpected wildcards, nested boolean operators, or attribute names not used by normal Netatalk queries.
Authenticated Netatalk sessions issuing repeated lookups against identity attributes such as uid, uidNumber, or memberOf.
Unexplained modifications to LDAP entries originating from the service account used by Netatalk for directory binds.

Detection Strategies

Enable verbose LDAP query logging on the directory server and alert on filter strings containing unusual character sequences such as *)(, )(|, or unescaped parentheses from Netatalk's bind DN.
Baseline normal Netatalk LDAP traffic and flag deviations in query length, attribute scope, or response size.
Correlate AFP authentication events with subsequent LDAP search and modify operations to identify abnormal user-to-query patterns.

Monitoring Recommendations

Forward Netatalk daemon logs and directory server access logs to a centralized log platform for retention and correlation.
Monitor for changes to LDAP entries that should be immutable in normal operation, such as group membership or objectClass attributes.
Track failed and successful authentications to the AFP service to identify credential stuffing or post-exploitation reuse.

How to Mitigate CVE-2026-44063

Immediate Actions Required

Inventory all Netatalk installations and identify any running versions 2.1.0 through 4.4.2.
Upgrade to the fixed release identified in the Netatalk Security Advisory.
Restrict the LDAP bind account used by Netatalk to the minimum read scope required, and remove write permissions where they are not needed.
Rotate the Netatalk LDAP bind credentials after patching to invalidate any captured secrets.

Patch Information

The Netatalk project has published remediation details in the Netatalk Security Advisory. Administrators should apply the vendor-supplied update for any installation in the affected range of 2.1.0 through 4.4.2 and verify the running binary version after upgrade.

Workarounds

Disable LDAP-backed lookups in Netatalk where the deployment can rely on local authentication backends instead.
Place Netatalk behind network segmentation that limits authenticated access to trusted client subnets only.
Apply strict input length and character restrictions on usernames and lookup fields exposed by the AFP service at the network or proxy layer.

bash

# Configuration example: verify installed Netatalk version and limit LDAP bind privileges
afpd -V
# Example: set read-only bind account in afp.conf and disable LDAP write operations
# [Global]
#   ldap auth method = simple
#   ldap auth dn = cn=netatalk-ro,ou=service,dc=example,dc=com
#   ldap server = ldaps://ldap.example.com