HighCVE-2026-18453

Red Hat: NULL Pointer Dereference (CVE-2026-18453)

Published 07.09.2026Last modified 08.10.2026Sources: SUSE, CVE.org, BSI

What is affected, what to do

A flaw was found in 389 Directory Server. A missing NULL pointer check in the paged results handling of op_shared_search allows an unauthenticated remote attacker to crash the LDAP server by sending a crafted sequence of search requests using the USE_ONE_BACKEND control, resulting in denial of service.

Update Red Hat Directory Server 11.5 E4S for RHEL 8 to version 8060020260908152739.0ca98e7e, Red Hat Directory Server 11.7 E4S for RHEL 8 to version 8080020260903102346.f969626e, Red Hat Directory Server 11.9 for RHEL 8 to version 8100020260904171440.37ed7c03.

Affected: Red Hat Directory Server 11.5 E4S for RHEL 8 lt *..8060020260908152739.0ca98e7e
Red Hat Directory Server 11.7 E4S for RHEL 8 lt *..8080020260903102346.f969626e
Red Hat Directory Server 11.9 for RHEL 8 lt *..8100020260904171440.37ed7c03
Red Hat Directory Server 12.2 E4S for RHEL 9 lt *..9020020260903155914.1674d574
Red Hat Directory Server 12.4 E4S for RHEL 9 lt *..9040020260903102623.1674d574
Red Hat Enterprise Linux 10 lt *..0:3.2.0-10.el10_2
Red Hat Enterprise Linux 10.0 Extended Update Support lt *..0:3.0.6-21.el10_0
Red Hat Enterprise Linux 7 Extended Lifecycle Support lt *..0:1.3.11.1-15.el7_9
Red Hat Enterprise Linux 8 lt *..8100020260904155442.25e700aa
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support lt *..8040020260901171549.96015a92
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On lt *..8040020260901171549.96015a92
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support lt *..8060020260901145727.824efc52
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On lt *..8060020260901145727.824efc52
Red Hat Enterprise Linux 8.8 Telecommunications Update Service lt *..8080020260831180218.6dbb3803
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions lt *..8080020260831180218.6dbb3803
Red Hat Enterprise Linux 9 lt *..0:2.8.0-10.el9_8
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions lt *..0:2.2.4-22.el9_2
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions lt *..0:2.4.5-29.el9_4
Red Hat Enterprise Linux 9.6 Extended Update Support lt *..0:2.6.1-24.el9_6
Red Hat Directory Server 13.2 lt *..1788851765
Fixed in: Red Hat Directory Server 11.5 E4S for RHEL 8 8060020260908152739.0ca98e7e
Red Hat Directory Server 11.7 E4S for RHEL 8 8080020260903102346.f969626e
Red Hat Directory Server 11.9 for RHEL 8 8100020260904171440.37ed7c03
Red Hat Directory Server 12.2 E4S for RHEL 9 9020020260903155914.1674d574
Red Hat Directory Server 12.4 E4S for RHEL 9 9040020260903102623.1674d574
Red Hat Enterprise Linux 10 0:3.2.0-10.el10_2
Red Hat Enterprise Linux 10.0 Extended Update Support 0:3.0.6-21.el10_0
Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:1.3.11.1-15.el7_9
Red Hat Enterprise Linux 8 8100020260904155442.25e700aa
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 8040020260901171549.96015a92
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 8040020260901171549.96015a92
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 8060020260901145727.824efc52
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 8060020260901145727.824efc52
Red Hat Enterprise Linux 8.8 Telecommunications Update Service 8080020260831180218.6dbb3803
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 8080020260831180218.6dbb3803
Red Hat Enterprise Linux 9 0:2.8.0-10.el9_8
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:2.2.4-22.el9_2
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:2.4.5-29.el9_4
Red Hat Enterprise Linux 9.6 Extended Update Support 0:2.6.1-24.el9_6
Red Hat Directory Server 13.2 1788851765

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Metrics

7.5

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: NVD, CVSS v3

7.5

CVSS v3

Severity High on the scale from 0 to 10.

Source: SUSE, CVE.org, BSI

0.9 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 58.1

Show all metrics

Severity: High
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 89.89 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: no public PoC known
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 7.5 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 7.5
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.9 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 58.1; High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 07.09.2026
CISA assessment (SSVC): Exploitation: none known · automatable · Technical impact: partial; Source: CISA Vulnrichment, as of 9 September 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-476

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

Source: suse_csaf, cvelistv5, NVD (NIST), BSI WID Portal, BSI CSAF

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
Red Hat	Red Hat Directory Server 11.5 E4S for RHEL 8	`< 8060020260908152739.0ca98e7e`	`8060020260908152739.0ca98e7e`
Red Hat	Red Hat Directory Server 11.7 E4S for RHEL 8	`< 8080020260903102346.f969626e`	`8080020260903102346.f969626e`
Red Hat	Red Hat Directory Server 11.9 for RHEL 8	`< 8100020260904171440.37ed7c03`	`8100020260904171440.37ed7c03`
Red Hat	Red Hat Directory Server 12	`—`	—
Red Hat	Red Hat Directory Server 12.2 E4S for RHEL 9	`< 9020020260903155914.1674d574`	`9020020260903155914.1674d574`
Red Hat	Red Hat Directory Server 12.4 E4S for RHEL 9	`< 9040020260903102623.1674d574`	`9040020260903102623.1674d574`
Red Hat	Red Hat Directory Server 13	`—`	—
Red Hat	Red Hat Directory Server 13.2	`< 1788851765`	`1788851765`
Red Hat	Red Hat Enterprise Linux 10	`< 0:3.2.0-10.el10_2`	`0:3.2.0-10.el10_2`
Red Hat	Red Hat Enterprise Linux 10.0 Extended Update Support	`< 0:3.0.6-21.el10_0`	`0:3.0.6-21.el10_0`
Red Hat	Red Hat Enterprise Linux 6	`—`	—
Red Hat	Red Hat Enterprise Linux 7 Extended Lifecycle Support	`< 0:1.3.11.1-15.el7_9`	`0:1.3.11.1-15.el7_9`
Red Hat	Red Hat Enterprise Linux 8	`< 8100020260904155442.25e700aa`	`8100020260904155442.25e700aa`
Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	`< 8040020260901171549.96015a92`	`8040020260901171549.96015a92`
Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	`< 8040020260901171549.96015a92`	`8040020260901171549.96015a92`
Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	`< 8060020260901145727.824efc52`	`8060020260901145727.824efc52`
Red Hat	Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	`< 8060020260901145727.824efc52`	`8060020260901145727.824efc52`
Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	`< 8080020260831180218.6dbb3803`	`8080020260831180218.6dbb3803`
Red Hat	Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	`< 8080020260831180218.6dbb3803`	`8080020260831180218.6dbb3803`
Red Hat	Red Hat Enterprise Linux 9	`< 0:2.8.0-10.el9_8`	`0:2.8.0-10.el9_8`
Red Hat	Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions	`< 0:2.2.4-22.el9_2`	`0:2.2.4-22.el9_2`
Red Hat	Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions	`< 0:2.4.5-29.el9_4`	`0:2.4.5-29.el9_4`
Red Hat	Red Hat Enterprise Linux 9.6 Extended Update Support	`< 0:2.6.1-24.el9_6`	`0:2.6.1-24.el9_6`
Red Hat	Directory Server	`11.9 for RHEL 8` `12.2 E4S for RHEL 9` `12.4 E4S for RHEL 9` `11.7 E4S for RHEL 8`	— — — —
Red Hat	Enterprise Linux	`8.8 Telecommunications Update Service` `8.4 Extended Update Support Long-Life Add-On` `8.4 Advanced Mission Critical Update Support` `9.2 Update Services for SAP Solutions` `8.8 Update Services for SAP` `7 Extended Lifecycle Support` `9.4 Update Services for SAP Solutions`	— — — — — — —

Vendors and products

Weakness classes (CWE)

CWE-476NULL Pointer Dereference
Base
The product dereferences a pointer that it expects to be valid but is NULL.
Entry at MITRE CWE-476

References & sources

access.redhat.comsecurity/cve/CVE-2026-18453Vulnerability database, x_refsource_REDHAT
bugzilla.redhat.comRHBZ#2509696Issue tracking, x_refsource_REDHAT
access.redhat.comRHSA-2026:64771Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64776Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64778Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64779Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64781Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64783Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64789Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64792Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64804Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64784Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64791Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64780Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64785Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64790Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:64793Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:65119Vendor advisory, x_refsource_REDHAT
access.redhat.comRHSA-2026:79217Vendor advisory, x_refsource_REDHAT

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

08.10.2026Record modifiedRed Hat

New references:

https://access.redhat.com/errata/RHSA-2026:79217

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:79217

Source identifier: secalert@redhat.com

09.09.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: none known, automatable: yes

Show the original change

Individual changes of this event as published by NVD
Type	Action	Before	After
SSVC assessment	added	—	{"id":"CVE-2026-18453","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-09-09T14:40:00.574684Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

08.09.2026Record modifiedRed Hat

New references:

https://access.redhat.com/errata/RHSA-2026:65119

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:65119

Source identifier: secalert@redhat.com

08.09.2026Record modifiedRed Hat

New references:

Show 5 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64780
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64785
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64790
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64793

Source identifier: secalert@redhat.com

08.09.2026Record modifiedRed Hat

New references:

https://access.redhat.com/errata/RHSA-2026:64784

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64784

Source identifier: secalert@redhat.com

Show 5 older changes

08.09.2026Record modifiedRed Hat

New references:

https://access.redhat.com/errata/RHSA-2026:64791

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64791

Source identifier: secalert@redhat.com

08.09.2026Record modifiedRed Hat

New references:

Show 3 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64783
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64804

Source identifier: secalert@redhat.com

08.09.2026Record modifiedRed Hat

New references:

and 2 more references

Show 7 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64776
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64778
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64779
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64781
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64789
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64792

Source identifier: secalert@redhat.com

08.09.2026Record modifiedRed Hat

New references:

https://access.redhat.com/errata/RHSA-2026:64771

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/errata/RHSA-2026:64771

Source identifier: secalert@redhat.com

07.09.2026ReceivedRed Hat

CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness type: CWE-476

Description added or changed

New references:

Show 6 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	A flaw was found in 389 Directory Server. A missing NULL pointer check in the paged results handling of op_shared_search allows an unauthenticated remote attacker to crash the LDAP server by sending a crafted sequence of search requests using the USE_ONE_BACKEND control, resulting in denial of service.
CVSS	added	—	AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness type (CWE)	added	—	CWE-476
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/18xxx/CVE-2026-18453.json">CVE-2026-18453</a>
Reference	added	—	https://access.redhat.com/security/cve/CVE-2026-18453
Reference	added	—	https://bugzilla.redhat.com/show_bug.cgi?id=2509696

Source identifier: secalert@redhat.com

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<a href="https://intel.neosec.eu/en/cve/CVE-2026-18453"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-18453.svg?lang=en" alt="CVE-2026-18453 – NEOSEC Intel" height="20"></a>