389-Ds SASL_IO Integer Overflow: DoS/RCE via Crafted Packet
CVE-2026-11774 Published on June 11, 2026

389-ds-base: 389-ds-base: integer overflow in sasl packet length bypasses size limit leading to heap buffer overflow
An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.

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Vulnerability Analysis

CVE-2026-11774 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 have a small impact on confidentiality and integrity, and a high impact on availability.

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

Timeline

Reported to Red Hat.

Made public. 49 days later.

Weakness Type

Integer Overflow or Wraparound

The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. An integer overflow or wraparound occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may wrap to become a very small or negative number. While this may be intended behavior in circumstances that rely on wrapping, it can have security consequences if the wrap is unexpected. This is especially the case if the integer overflow can be triggered using user-supplied inputs. This becomes security-critical when the result is used to control looping, make a security decision, or determine the offset or size in behaviors such as memory allocation, copying, concatenation, etc.


Products Associated with CVE-2026-11774

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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

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: 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
0.67%
Percentile
48.23%

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.