CVE-2026-19271 Overview
CVE-2026-19271 is an LDAP injection vulnerability in TÜBİTAK BİLGEM Software Technologies Research Institute Liderahenk. The flaw stems from improper neutralization of special elements used in a Lightweight Directory Access Protocol (LDAP) query [CWE-90]. Attackers can send crafted input over the network without authentication or user interaction. Successful exploitation exposes directory contents and can disclose sensitive information stored in the LDAP backend. The vulnerability affects Liderahenk versions 3.4.0 through versions prior to 3.5.5.
Critical Impact
Unauthenticated attackers can inject LDAP metacharacters into queries to enumerate or extract directory data managed by Liderahenk.
Affected Products
- TÜBİTAK BİLGEM Liderahenk 3.4.0
- TÜBİTAK BİLGEM Liderahenk versions between 3.4.0 and 3.5.5
- TÜBİTAK BİLGEM Liderahenk releases prior to 3.5.5
Discovery Timeline
- 2026-08-26 - CVE-2026-19271 published to the National Vulnerability Database
- 2026-08-26 - Last updated in the NVD database
Technical Details for CVE-2026-19271
Vulnerability Analysis
Liderahenk is a Linux endpoint management system used by TÜBİTAK BİLGEM to administer directory-integrated clients. The product relies on LDAP for identity, group, and policy operations. CVE-2026-19271 exists because user-supplied input reaches an LDAP query without proper sanitization or parameterization. Attackers can inject LDAP filter metacharacters such as *, (, ), |, and & to alter query logic. The manipulated query returns directory entries the caller was not intended to access. The impact is confined to confidentiality, with no direct impact on integrity or availability of the LDAP directory.
Root Cause
The root cause is improper neutralization of special elements passed into an LDAP search filter. The application concatenates untrusted input into the filter string instead of using safe encoding routines or bound parameters. This is a canonical instance of CWE-90 and applies across the affected version range from 3.4.0 up to but not including 3.5.5.
Attack Vector
The attack vector is network-based and requires no privileges or user interaction. An attacker sends a request containing LDAP filter metacharacters to a Liderahenk endpoint that constructs a directory query from the input. The injected characters break out of the intended filter context and add attacker-controlled clauses. The resulting query returns unintended directory entries and attribute values.
No public exploit code is available. See the Siber Güvenlik Notification TR-26-0916 for vendor context.
Detection Methods for CVE-2026-19271
Indicators of Compromise
- LDAP query logs on the directory server containing filter fragments such as )(uid=*, )(|(cn=*, or unbalanced parentheses originating from Liderahenk service accounts.
- Unusually large LDAP search responses returning attributes outside the expected schema scope of Liderahenk operations.
- Repeated failed or malformed LDAP searches followed by successful broad-scope searches from the same client session.
Detection Strategies
- Enable verbose LDAP audit logging on the backing directory service and alert on filters that contain wildcard characters injected mid-token.
- Deploy a web application firewall or reverse proxy in front of Liderahenk to inspect requests for LDAP metacharacters in parameters that map to directory queries.
- Baseline normal Liderahenk query patterns and flag deviations in search base, filter length, and attribute selection.
Monitoring Recommendations
- Forward Liderahenk application logs and directory server logs into a centralized log platform for correlation.
- Monitor for spikes in directory read volume tied to the Liderahenk service account outside of scheduled tasks.
- Track authentication and query patterns from unauthenticated network sources reaching Liderahenk endpoints.
How to Mitigate CVE-2026-19271
Immediate Actions Required
- Upgrade Liderahenk to version 3.5.5 or later on all servers running an affected release from the 3.4.0 to pre-3.5.5 range.
- Restrict network access to Liderahenk management interfaces so only trusted administrative networks can reach them.
- Rotate credentials used by Liderahenk to bind to the LDAP directory if injection activity is suspected in logs.
Patch Information
TÜBİTAK BİLGEM addresses CVE-2026-19271 in Liderahenk 3.5.5. Consult the Siber Güvenlik Notification TR-26-0916 for the official advisory and release guidance. Confirm the installed version after the update using the vendor-supplied version command.
Workarounds
- Place Liderahenk behind a reverse proxy that strips or rejects LDAP filter metacharacters in request parameters until patching is complete.
- Limit the LDAP bind account used by Liderahenk to the minimum search base and attribute set required for its function.
- Monitor and rate-limit unauthenticated requests to Liderahenk endpoints to slow reconnaissance and injection attempts.
# Configuration example: verify installed Liderahenk version and confirm remediation
dpkg -l | grep -i liderahenk
# Expected output should show version 3.5.5 or later after patching
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
