389-ds-base 1.3.2+ Heap Buffer Overflow via oversized LDAP UNBIND
CVE-2026-11610 Published on July 7, 2026

389-ds-base: 389-ds-base: heap buffer overflow in sasl_io_recv() via padded sasl unbind
A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). After a successful SASL bind with integrity protection (SSF > 0), an authenticated attacker can send a specially crafted oversized LDAP UNBIND packet that is copied into a 512-byte heap receive buffer without a bounds check in sasl_io_recv() in sasl_io.c. This allows up to approximately 2 megabytes of attacker-controlled data to overflow the buffer, causing a denial of service (server crash). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, any enrolled host, or any service account can trigger this vulnerability over the network after authenticating via GSSAPI. The vulnerable code path has existed since approximately 2013 (389-ds-base 1.3.2) and was not addressed by the CVE-2025-14905 fix, which patched a separate heap overflow in schema.c only.

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Vulnerability Analysis

CVE-2026-11610 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 76 days later.

Weakness Type

Heap-based Buffer Overflow

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().


Products Associated with CVE-2026-11610

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Red Hat Directory Server
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Directory Server E4s
 
Red Hat Rhel E4s
 
Red Hat Rhel Tus
 
Red Hat Rhel Els
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus Long Life
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel Eus
 

Affected Versions

389ds 389-ds-base: Red Hat Directory Server 11.5 E4S for RHEL 8: Red Hat Directory Server 11.7 E4S for RHEL 8: Red Hat Directory Server 11.9 for RHEL 8: Red Hat Directory Server 12.2 E4S for RHEL 9: Red Hat Directory Server 12.4 E4S for RHEL 9: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 7 Extended Lifecycle Support: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Directory Server 13.2: Red Hat Directory Server 12: Red Hat Directory Server 13: Red Hat Enterprise Linux 6:

Exploit Probability

EPSS
0.63%
Percentile
46.39%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.