# CVE-2026-9064: Denial of service in Red Hat Directory Server 11.5 E4S for RHEL 8 > Remote unauthenticated attackers can cause denial of service in 389-ds-base by sending LDAP requests with excessive controls, exhausting server resources. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 20 May 2026 - **Updated:** 21 Aug 2026 - **Also known as:** ALSA-2026:26455, ALSA-2026:26459, CLSA-2026-1782219057, CLSA-2026-1782219956, DEBIAN-CVE-2026-9064, GHSA-7r3c-wfgh-x96c, MGASA-2026-0310, OESA-2026-3128, OESA-2026-3129, OESA-2026-3130, OESA-2026-3131, RHSA-2026:26452, RHSA-2026:26453, RHSA-2026:26454, RHSA-2026:26455, RHSA-2026:26456, RHSA-2026:26457, RHSA-2026:26458, RHSA-2026:26459, RHSA-2026:26460, RHSA-2026:26461, RHSA-2026:26463, RHSA-2026:26464, RHSA-2026:26465, RHSA-2026:26597, RHSA-2026:26599, RHSA-2026:26639, RLSA-2026:26455, RLSA-2026:26456, RLSA-2026:26459, SUSE-SU-2026:2316-1, SUSE-SU-2026:2417-1, SUSE-SU-2026:2418-1, SUSE-SU-2026:2419-1, UBUNTU-CVE-2026-9064, openSUSE-SU-2026:10870-1 ## What is CVE-2026-9064? CVE-2026-9064 is a high-severity denial of service vulnerability in Redhat Enterprise Linux, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function in the LDAP server does not enforce an upper bound on the number of controls per LDAP message. A remote, unauthenticated attacker can send a specially crafted LDAP request containing hundreds of thousands of minimal controls within the default maximum BER message size (2 MB), causing excessive CPU consumption and heap allocation on the server. Under concurrent exploitation, this leads to significant latency degradation, worker thread starvation, or out-of-memory termination, resulting in a denial of service. Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling) ## Which versions are affected by CVE-2026-9064? It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `389-ds-base` | AlmaLinux:8 | All versions | 1.4.3.39-24.module_el8.10.0+4196+be88fbc7 | | `389-ds-base-devel` | AlmaLinux:8 | All versions | 1.4.3.39-24.module_el8.10.0+4196+be88fbc7 | | `389-ds-base-legacy-tools` | AlmaLinux:8 | All versions | 1.4.3.39-24.module_el8.10.0+4196+be88fbc7 | | `389-ds-base-libs` | AlmaLinux:8 | All versions | 1.4.3.39-24.module_el8.10.0+4196+be88fbc7 | | `389-ds-base-snmp` | AlmaLinux:8 | All versions | 1.4.3.39-24.module_el8.10.0+4196+be88fbc7 | | `python3-lib389` | AlmaLinux:8 | All versions | 1.4.3.39-24.module_el8.10.0+4196+be88fbc7 | | `389-ds-base` | AlmaLinux:9 | All versions | 2.8.0-7.el9_8 | | `389-ds-base-devel` | AlmaLinux:9 | All versions | 2.8.0-7.el9_8 | | `389-ds-base-libs` | AlmaLinux:9 | All versions | 2.8.0-7.el9_8 | | `389-ds-base-snmp` | AlmaLinux:9 | All versions | 2.8.0-7.el9_8 | | `python3-lib389` | AlmaLinux:9 | All versions | 2.8.0-7.el9_8 | | `389-ds-base` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-debuginfo` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-debugsource` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-devel` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-legacy-tools` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-legacy-tools-debuginfo` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-libs` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-libs-debuginfo` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-snmp` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base-snmp-debuginfo` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `cockpit-389-ds` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `python3-lib389` | Red Hat:directory_server:11.9::el8 | All versions | 0:1.4.3.39-24.module+el8dsrv+24341+2b6b9665 | | `389-ds-base` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-debuginfo` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-debugsource` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-devel` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-legacy-tools` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-legacy-tools-debuginfo` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-libs` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-libs-debuginfo` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-snmp` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base-snmp-debuginfo` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `cockpit-389-ds` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `python3-lib389` | Red Hat:directory_server_e4s:11.5::el8 | All versions | 0:1.4.3.34-6.module+el8dsrv+24373+7e48d0d8 | | `389-ds-base` | Red Hat:directory_server_e4s:11.7::el8 | All versions | 0:1.4.3.34-15.module+el8dsrv+24378+c77f3fdd | | `389-ds-base-debuginfo` | Red Hat:directory_server_e4s:11.7::el8 | All versions | 0:1.4.3.34-15.module+el8dsrv+24378+c77f3fdd | | `389-ds-base-debugsource` | Red Hat:directory_server_e4s:11.7::el8 | All versions | 0:1.4.3.34-15.module+el8dsrv+24378+c77f3fdd | | `389-ds-base-devel` | Red Hat:directory_server_e4s:11.7::el8 | All versions | 0:1.4.3.34-15.module+el8dsrv+24378+c77f3fdd | | `389-ds-base-legacy-tools` | Red Hat:directory_server_e4s:11.7::el8 | All versions | 0:1.4.3.34-15.module+el8dsrv+24378+c77f3fdd | Products: Redhat 389 Directory Server, Redhat Directory Server, Redhat Enterprise Linux. ## How do I fix CVE-2026-9064? Apply the vendor's patch. ## Is CVE-2026-9064 being exploited? There is no known exploitation of CVE-2026-9064 in the wild and no public exploit code. ## Other vulnerabilities in Redhat Enterprise Linux - [CVE-2026-11770](https://insights.sbomify.com/CVE-2026-11770/): 389-ds-base: 389-ds-base: pre-auth ldap filter injection in cleanallruv status check (high 7.5) - [CVE-2026-15722](https://insights.sbomify.com/CVE-2026-15722/): Memory corruption in Red Hat Directory Server 11.5 E4S for RHEL 8 (high 7.5) - [CVE-2010-2222](https://insights.sbomify.com/CVE-2010-2222/): Null dereference in Red Hat Directory Server (high 7.5) - [CVE-2026-11611](https://insights.sbomify.com/CVE-2026-11611/): 389-ds-base: 389-ds-base: content sync plugin unbounded queue growth and race conditions (medium 6.5) - [CVE-2024-6237](https://insights.sbomify.com/CVE-2024-6237/): 389-ds-base: unauthenticated user can trigger a dos by sending a specific extended search request (medium 6.5) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-9064 and fix it if it is affected. What it is: CVE-2026-9064 is a high-severity denial of service vulnerability in Redhat Enterprise Linux, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-9064 in the wild and no public exploit code. Affected product: Redhat Enterprise Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-9064/ (Markdown: https://insights.sbomify.com/CVE-2026-9064/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9064 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9064 - OSV: https://osv.dev/vulnerability/CVE-2026-9064 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-9064/ Summaries are generated and may contain mistakes; the official description above is the record.