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7.5 High

CVE-2026-18355 389-ds-base: 389-ds-base: heap buffer overflow via sasl wrapped-record length lower-bound underflow in sasl_io_start_packet()

Description

A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), the wrapped-record length read from the wire is validated only against an upper bound. A small wire length (0, 1, or 2) produces an encrypted_buffer_count below the already-consumed encrypted_buffer_offset, causing an unsigned subtraction underflow in sasl_io_read_packet(). PR_Recv is then requested to read approximately 4 GiB into a 1024-byte heap buffer, resulting in a heap buffer overflow with attacker-controlled content. After a successful SASL bind with integrity protection (SSF > 0), a remote authenticated attacker can cause a denial of service or potentially achieve remote code execution. This flaw is distinct from CVE-2026-11774, whose fix only guards against upper-bound overflow.

CVSS 3.1 detail

Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitable remotely over the network, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector
Network
Attack complexity
High
Privileges required
Low
Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Affected products and versions

Product Affected versions Fixed in
Red Hat Directory Server 11 Versions not published
Red Hat Directory Server 12 Versions not published
Red Hat Directory Server 13 Versions not published
Red Hat Enterprise Linux 10 Versions not published
Red Hat Enterprise Linux 6 Versions not published
Red Hat Enterprise Linux 7 Versions not published
Red Hat Enterprise Linux 8 8100020260904155442.25 earliest → < 8100020260904155442.25e700aa 8100020260904155442.25e700aa
Red Hat Enterprise Linux 9 Versions not published
Red Hat Enterprise Linux 7 Extended Lifecycle Support Versions not published
Show the 16 other branches
Product Affected versions Fixed in
Red Hat Directory Server 11.7 E4S for RHEL 8 8080020260903102346 earliest → < 8080020260903102346.f969626e 8080020260903102346.f969626e
Red Hat Directory Server 12.2 E4S for RHEL 9 9020020260903155914.1674 earliest → < 9020020260903155914.1674d574 9020020260903155914.1674d574
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 8040020260901171549.96015 earliest → < 8040020260901171549.96015a92 8040020260901171549.96015a92
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 8040020260901171549.96015 earliest → < 8040020260901171549.96015a92 8040020260901171549.96015a92
Red Hat Enterprise Linux 8.8 Telecommunications Update Service 8080020260831180218.6 earliest → < 8080020260831180218.6dbb3803 8080020260831180218.6dbb3803
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 8080020260831180218.6 earliest → < 8080020260831180218.6dbb3803 8080020260831180218.6dbb3803
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Versions not published
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Versions not published
Red Hat Enterprise Linux 10.0 Extended Update Support Versions not published
Red Hat Enterprise Linux 9.6 Extended Update Support Versions not published
Red Hat Directory Server 11.9 for RHEL 8 8100020260904171440.37 earliest → < 8100020260904171440.37ed7c03 8100020260904171440.37ed7c03
Red Hat Directory Server 12.4 E4S for RHEL 9 9040020260903102623.1674 earliest → < 9040020260903102623.1674d574 9040020260903102623.1674d574
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 8060020260901145727.824 earliest → < 8060020260901145727.824efc52 8060020260901145727.824efc52
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 8060020260901145727.824 earliest → < 8060020260901145727.824efc52 8060020260901145727.824efc52
Red Hat Directory Server 13.2 1788851765 earliest → < 1788851765 1788851765
Red Hat Directory Server 11.5 E4S for RHEL 8 8060020260908152739.0 earliest → < 8060020260908152739.0ca98e7e 8060020260908152739.0ca98e7e

References

Timeline

  1. Published
  2. Last modified

Other CVEs of Red Hat Directory Server 11

The 42 CVEs of Red Hat Directory Server 11 →
CVE-2026-117548 389-ds-base: 389-ds-base: null pointer dereference via modifydn using an attribute's schema alias name causes denial of service 6.5 Medium CVE-2026-86345 389-ds-base: 389-ds-base: starttls plaintext-buffer retention allows on-path attacker to forge an ldap client's authentication result 9.0 Critical CVE-2026-86344 389-ds-base: 389-ds-base: unauthenticated worker-thread-pool exhaustion via completed-operation-then-incomplete-pdu connection requeue 7.5 High CVE-2026-19843 389-ds-base: 389-ds-base: command injection via unescaped ldap dn in cockpit 389 console ldap editor 8.4 High
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