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()
Quick assessment
Affected
Red Hat Red Hat Directory Server 11.5 E4S for RHEL 8
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
389 Directory Server是389 Directory Server团队开源的一款目录服务器软件。 389 Directory Server (389-ds-base)存在数字错误漏洞，该漏洞源于SASL I/O层对包裹记录长度仅进行上界验证，导致无符号减法下溢和堆缓冲区溢出。远程认证攻击者成功利用此漏洞可导致拒绝服务或远程代码执行。受影响的产品包括Red Hat Directory Server 11版本和12版本，以及Red Hat Enterprise Linux 7版本、8版本、9版
Possible ATT&CK Techniques 1 AI
T1210 · Exploitation of Remote ServicesAffected Version Matrix 23
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I. Basic Information for CVE-2026-18355
Vulnerability Information
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Vulnerability Title
389-ds-base: 389-ds-base: heap buffer overflow via sasl wrapped-record length lower-bound underflow in sasl_io_start_packet()
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
整数下溢(超界折返)
Source: CVE Program / CVE List V5
Vulnerability Title
389 Directory Server 数字错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
389 Directory Server是389 Directory Server团队开源的一款目录服务器软件。 389 Directory Server (389-ds-base)存在数字错误漏洞，该漏洞源于SASL I/O层对包裹记录长度仅进行上界验证，导致无符号减法下溢和堆缓冲区溢出。远程认证攻击者成功利用此漏洞可导致拒绝服务或远程代码执行。受影响的产品包括Red Hat Directory Server 11版本和12版本，以及Red Hat Enterprise Linux 7版本、8版本、9版
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Red Hat | Red Hat Directory Server 11.5 E4S for RHEL 8 | 8060020260908152739.0ca98e7e ~ * |
cpe:/a:redhat:directory_server_e4s:11.5::el8
|
|
| Red Hat | Red Hat Directory Server 11.7 E4S for RHEL 8 | 8080020260903102346.f969626e ~ * |
cpe:/a:redhat:directory_server_e4s:11.7::el8
|
|
| Red Hat | Red Hat Directory Server 11.9 for RHEL 8 | 8100020260904171440.37ed7c03 ~ * |
cpe:/a:redhat:directory_server:11.9::el8
|
|
| Red Hat | Red Hat Directory Server 12.2 E4S for RHEL 9 | 9020020260903155914.1674d574 ~ * |
cpe:/a:redhat:directory_server_e4s:12.2::el9
|
|
| Red Hat | Red Hat Directory Server 12.4 E4S for RHEL 9 | 9040020260903102623.1674d574 ~ * |
cpe:/a:redhat:directory_server_e4s:12.4::el9
|
|
| Red Hat | Red Hat Enterprise Linux 10 | 0:3.2.0-10.el10_2 ~ * |
cpe:/o:redhat:enterprise_linux:10.2
|
|
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | 0:3.0.6-21.el10_0 ~ * |
cpe:/o:redhat:enterprise_linux_eus:10.0
|
|
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | 0:1.3.11.1-15.el7_9 ~ * |
cpe:/o:redhat:rhel_els:7
|
|
| Red Hat | Red Hat Enterprise Linux 8 | 8100020260904155442.25e700aa ~ * |
cpe:/a:redhat:enterprise_linux:8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | 8040020260901171549.96015a92 ~ * |
cpe:/a:redhat:rhel_aus:8.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | 8040020260901171549.96015a92 ~ * |
cpe:/a:redhat:rhel_aus:8.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | 8060020260901145727.824efc52 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | 8060020260901145727.824efc52 ~ * |
cpe:/a:redhat:rhel_aus:8.6::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | 8080020260831180218.6dbb3803 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | 8080020260831180218.6dbb3803 ~ * |
cpe:/a:redhat:rhel_e4s:8.8::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9 | 0:2.8.0-10.el9_8 ~ * |
cpe:/a:redhat:enterprise_linux:9::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | 0:2.2.4-22.el9_2 ~ * |
cpe:/a:redhat:rhel_e4s:9.2::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | 0:2.4.5-29.el9_4 ~ * |
cpe:/a:redhat:rhel_e4s:9.4::appstream
|
|
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | 0:2.6.1-24.el9_6 ~ * |
cpe:/a:redhat:rhel_eus:9.6::appstream
|
|
| Red Hat | Red Hat Directory Server 13.2 | 1788851765 ~ * |
cpe:/a:redhat:directory_server:13.2::el10
|
|
| Red Hat | Red Hat Directory Server 12 | - |
cpe:/a:redhat:directory_server:12
|
|
| Red Hat | Red Hat Directory Server 13 | - |
cpe:/a:redhat:directory_server:13
|
|
| Red Hat | Red Hat Enterprise Linux 6 | - |
cpe:/o:redhat:enterprise_linux:6
|
|
II. Public POCs for CVE-2026-18355
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
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Vendor Advisories for CVE-2026-18355 (14)
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🔗 RHSA-2026:64790 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64791 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64789 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64771 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64804 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64776 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64785 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
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🔗 RHSA-2026:64783 - Security Advisory - Red Hat Customer Portal Read full article vendor-advisory x_refsource_REDHAT
Other References for CVE-2026-18355 (5)
Same Patch Batch · Red Hat · 2026-09-07 · 10 CVEs total
| CVE-2026-18922 | 9.8 CRITICAL | 389-ds-base: 389-ds-base: sasl plain authentication allows privilege escalation to directo |
| CVE-2026-76578 | 9.8 CRITICAL | Ipa: freeipa: freeipa: unauthenticated ldap client can obtain administrator credentials vi |
| CVE-2026-86404 | 8.8 HIGH | Artemis-server: artemis-jms-client: artemis-core-client: undertow-core: wildfly-messaging- |
| CVE-2026-19843 | 8.4 HIGH | 389-ds-base: 389-ds-base: command injection via unescaped ldap dn in cockpit 389 console l |
| CVE-2026-79678 | 8.1 HIGH | Freeipa: idm: freeipa: idp-add eval() reachable before authorization check allows environm |
| CVE-2026-18453 | 7.5 HIGH | 389-ds-base: 389-ds-base: pre-authentication null pointer dereference via paged results an |
| CVE-2026-76560 | 7.5 HIGH | 389-ds-base: 389-ds: anonymous ldap client can defeat selfdn aci bind-rule checks via empt |
| CVE-2026-86332 | 6.5 MEDIUM | Odh-dashboard: odh-dashboard: nim credential secret readable by any authenticated user |
| CVE-2026-86469 | 5.3 MEDIUM | Glib2: toctou symlink race in `g_file_create_replace_destination` fallback path |
IV. Related Vulnerabilities
Same product: Red Hat Directory Server 11.5 E4S for RHEL 8
-
CVE-2026-19843
389-ds-base: 389-ds-base: command injection via unescaped ld -
CVE-2026-18922
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CVE-2026-18453
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CVE-2026-76560
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CVE-2026-11770
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-
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V. Comments for CVE-2026-18355
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