CVE-2025-14905: 
Rocky Linux vulnerability analysis and mitigation

CVE-2025-14905 is a heap-based buffer overflow vulnerability in the schema_attr_enum_callback function within schema.c of the 389-ds-base (389 Directory Server) LDAP server. The flaw arises from incorrect buffer size calculation when summing alias string lengths without accounting for additional formatting characters, which can lead to a heap overflow when a large number of aliases are processed. It affects 389-ds-base as shipped with Red Hat Enterprise Linux 9 and 10, as well as downstream distributions including Rocky Linux, AlmaLinux, Oracle Linux, Amazon Linux 2, SUSE, and openSUSE. The vulnerability was published on February 23, 2026, with Red Hat issuing patches the following day. It carries a CVSS v3.1 base score of 7.2 (High) (Red Hat RHSA-2026:3189, Feedly).

The root cause is classified as CWE-122 (Heap-based Buffer Overflow). In the schema_attr_enum_callback function in schema.c, the code calculates the output buffer size by summing the lengths of attribute alias strings but fails to account for additional formatting characters (e.g., separators, null terminators) that are written into the buffer. When a schema attribute with a sufficiently large number of aliases is processed, the resulting write exceeds the allocated heap buffer. The attack vector is network-based (LDAP), requires high privileges (authenticated administrator-level access), and no user interaction. An attacker with administrative LDAP credentials can trigger the overflow by submitting a crafted schema modification request containing a large number of aliases (Feedly, Red Hat RHSA-2026:3189).

Successful exploitation can result in Denial of Service (DoS) by crashing the 389 Directory Server process, or potentially Remote Code Execution (RCE) by corrupting heap memory in a controlled manner. Because 389-ds-base serves as the backend for Red Hat Identity Management (IdM/FreeIPA) and other LDAP-dependent services, a crash or compromise of the directory server could disrupt authentication and authorization across an entire enterprise environment. Confidentiality, integrity, and availability are all rated as HIGH impact, meaning a successful RCE could expose directory data (including credentials and group memberships), allow unauthorized modifications to directory entries, and take the LDAP service offline (Feedly, Red Hat RHSA-2026:3189).

No public proof-of-concept exploit code or in-the-wild exploitation has been reported as of the time of this report. The EPSS score is approximately 0.273%, indicating a low current probability of exploitation in the wild. The vulnerability requires high privileges (administrative LDAP credentials) to exploit, which significantly limits the attacker pool. It has not been added to the CISA Known Exploited Vulnerabilities (KEV) catalog. Detection coverage is broad, with multiple Nessus and Qualys scanner plugins available (Feedly).

1. Reconnaissance: Identify 389-ds-base (or Red Hat Directory Server / FreeIPA) instances on the network, typically listening on TCP port 389 (LDAP) or 636 (LDAPS). Confirm the version is unpatched (e.g., RHEL 9 with 389-ds-base < 2.7.0-10.el9_7, or RHEL 10 with 389-ds-base < 3.1.3-7.el10_1).
2. Obtain administrative credentials: Exploitation requires high-privilege LDAP credentials (e.g., cn=Directory Manager or equivalent). This may be obtained through credential theft, phishing, or reuse of compromised accounts.
3. Craft malicious schema modification: Construct an LDAP schema modification request (LDIF) that defines an attribute type with an abnormally large number of aliases (NAME values), designed to overflow the buffer size calculation in schema_attr_enum_callback.
4. Submit the request: Use an LDAP client (e.g., ldapmodify) to submit the crafted schema modification to the target server:

   ldapmodify -H ldap://<target>:389 -D "cn=Directory Manager" -w <password> -f malicious_schema.ldif

5. Trigger the overflow: The server processes the alias list, miscalculates the buffer size, and writes beyond the allocated heap region, causing either a crash (DoS) or, with a carefully crafted payload, potential code execution in the context of the ns-slapd process (Feedly, Red Hat RHSA-2026:3189).

• Logs: Unexpected crash or core dump of the ns-slapd process recorded in /var/log/dirsrv/slapd-<instance>/errors; error messages referencing schema processing or schema_attr_enum_callback in directory server logs.
• Process: Abnormal termination of the ns-slapd daemon; system crash reports or core files in /var/lib/dirsrv/ or /tmp/.
• Network: LDAP connections from unexpected source IPs performing schema modification operations (LDAP extended operations or modifyDN to cn=schema); high-volume or repeated schema modification requests on port 389/636.
• File System: Unexpected core dump files (e.g., core.*) in the 389-ds working directory; new or modified files in the directory server installation path following a crash.

Red Hat has released patched packages addressing CVE-2025-14905 across multiple RHEL versions:

• RHEL 9: 389-ds-base-2.7.0-10.el9_7 (RHSA-2026:3189, issued 2026-02-24)
• RHEL 9.6 EUS: 389-ds-base-2.6.1-20.el9_6 (RHSA-2026:4207, issued 2026-03-10)
• RHEL 10: 389-ds-base-3.1.3-7.el10_1 (RHSA-2026:3208, issued 2026-02-24)
• RHEL 10.0 EUS: 389-ds-base-3.0.6-17.el10_0 (RHSA-2026:3504, issued 2026-03-02)

Patches are also available for Rocky Linux (RLSA-2026:3208), AlmaLinux (ALSA-2026-5513), Amazon Linux 2 (ALAS2-2026-3205), SUSE (SUSE-SU-2026:0913-1, SUSE-SU-2026:1753-1), and openSUSE. The primary remediation is to apply the vendor-provided update immediately. As a temporary workaround, restrict LDAP administrative access to trusted networks and enforce strong credential controls to limit the attacker's ability to authenticate with high privileges (Red Hat RHSA-2026:3189, Red Hat RHSA-2026:3208, Red Hat RHSA-2026:3504).

Red Hat rated the vulnerability as "Moderate" severity in its advisories, despite the CVSS 7.2 (High) score, likely due to the high-privilege prerequisite for exploitation. The vulnerability received coverage from Linux security news aggregators including LinuxSecurity.com, pro-linux.de, and linuxcompatible.org, as well as automated social media posts from security accounts such as RedPacketSecurity on Mastodon. No notable independent researcher commentary or significant community debate has been identified beyond standard advisory distribution (Red Hat RHSA-2026:3189, Feedly).