CVE-2026-9064

389-ds-base: 389-ds-base: unbounded ldap controls count in get_ldapmessage_controls_ext() causes cpu and heap amplification (remote dos)

publishedCWE-770

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.

Technical severity7.5 highCVSS 3.1 · CNA: redhat

Published2026-05-20Source updated 2026-11-05

Collected2026-11-052 attributed sources

Fixes and workarounds

Workaround

Restrict network access to the LDAP port (389/tcp, 636/tcp) to trusted networks only using firewall rules or network ACLs. This prevents untrusted remote attackers from reaching the vulnerable code path. Optionally, lower the nsslapd-maxbersize configuration parameter to reduce the maximum BER message size accepted by the server. Note that this caps bytes, not the number of controls, and does not fully eliminate the amplification. Setting it too low may impact legitimate LDAP operations with large payloads.

Source: CNA: redhat

Fix

RHSA-2026:26453: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS) RHSA-2026:26458: Red Hat Directory Server 11.9 for RHEL 8 RHSA-2026:26457: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) RHSA-2026:26456: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) RHSA-2026:26459: Red Hat Enterprise Linux AppStream (v. 8) RHSA-2026:26463: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) RHSA-2026:26460: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) RHSA-2026:26454: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8) RHSA-2026:26452: Red Hat Enterprise Linux AppStream E4S (v.9.2) RHSA-2026:26464: Red Hat Enterprise Linux AppStream E4S (v.9.4) RHSA-2026:26465: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6) RHSA-2026:26455: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) RHSA-2026:26461: Red Hat Directory Server 11.5 E4S for RHEL 8 RHSA-2026:26597: Red Hat Directory Server 11.7 E4S for RHEL 8 RHSA-2026:26639: Red Hat Directory Server 12.2 E4S for RHEL 9 RHSA-2026:26599: Red Hat Directory Server 12.4 E4S for RHEL 9 RHSA-2026:27125: Red Hat Directory Server 13.2

Source: ADP: redhat-SADP

Workaround

Source: ADP: redhat-SADP

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
`389-ds-base` https://github.com/389ds/389-ds-base	0 (affected)	CNA: redhat
Red Hat Directory Server 11.5 E4S for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260609102432.0ca98e7e; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 11.7 E4S for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260610130252.f969626e; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 11.9 for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8100020260601104139.37ed7c03; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 12.2 E4S for RHEL 9 Red Hat `redhat-ds:12` https://access.redhat.com/downloads/content/package-browser/	≥ 9020020260615123354.1674d574; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 12.4 E4S for RHEL 9 Red Hat `redhat-ds:12` https://access.redhat.com/downloads/content/package-browser/	≥ 9040020260611130021.1674d574; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 10 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:3.2.0-7.el10_2; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 10.0 Extended Update Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:3.0.6-18.el10_0; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 7 Extended Lifecycle Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:1.3.11.1-12.el7_9; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8 Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8100020260601102239.25e700aa; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8040020260609102422.96015a92; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8040020260609102422.96015a92; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260609102416.824efc52; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260609102416.824efc52; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.8 Telecommunications Update Service Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260610125847.6dbb3803; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260610125847.6dbb3803; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.8.0-7.el9_8; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.2.4-18.el9_2; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.4.5-25.el9_4; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 9.6 Extended Update Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.6.1-21.el9_6; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 13.2 Red Hat `dirsrv/dirsrv-container-rhel10` https://catalog.redhat.com/software/containers/	≥ 1781714123; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat Directory Server 12 Red Hat `redhat-ds:12/389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Directory Server 13 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 6 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unknown	CNA: redhat
Red Hat Directory Server 11.5 E4S for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260609102432.0ca98e7e; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 11.7 E4S for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260610130252.f969626e; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 11.9 for RHEL 8 Red Hat `redhat-ds:11` https://access.redhat.com/downloads/content/package-browser/	≥ 8100020260601104139.37ed7c03; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 12.2 E4S for RHEL 9 Red Hat `redhat-ds:12` https://access.redhat.com/downloads/content/package-browser/	≥ 9020020260615123354.1674d574; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 12.4 E4S for RHEL 9 Red Hat `redhat-ds:12` https://access.redhat.com/downloads/content/package-browser/	≥ 9040020260611130021.1674d574; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 10 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:3.2.0-7.el10_2; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 10.0 Extended Update Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:3.0.6-18.el10_0; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 7 Extended Lifecycle Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:1.3.11.1-12.el7_9; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8 Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8100020260601102239.25e700aa; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8040020260609102422.96015a92; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8040020260609102422.96015a92; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260609102416.824efc52; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8060020260609102416.824efc52; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8.8 Telecommunications Update Service Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260610125847.6dbb3803; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Red Hat `389-ds:1.4` https://access.redhat.com/downloads/content/package-browser/	≥ 8080020260610125847.6dbb3803; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 9 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.8.0-7.el9_8; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.2.4-18.el9_2; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.4.5-25.el9_4; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 9.6 Extended Update Support Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.6.1-21.el9_6; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 13.2 Red Hat `dirsrv/dirsrv-container-rhel10` https://catalog.redhat.com/software/containers/	≥ 1781714123; < * (unaffected, rpm) Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 12 Red Hat `redhat-ds:12/389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	ADP: redhat-SADP
Red Hat Directory Server 13 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	ADP: redhat-SADP
Red Hat Enterprise Linux 6 Red Hat `389-ds-base` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unknown	ADP: redhat-SADP

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 7.5 high	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`	CNA: redhat
3.1 / 7.5 high	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`	ADP: redhat-SADP

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://access.redhat.com/errata/RHSA-2026:26452CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26453CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26454CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26455CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26456CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26457CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26458CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26459CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26460CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26461CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26463CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26464CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26465CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26597CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26599CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26639CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:27125CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-9064CNA: redhat · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2480093CNA: redhat · issue-tracking, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-9064ADP: redhat-SADP · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2480093ADP: redhat-SADP · issue-tracking, x_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9064.jsonADP: redhat-SADP · x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:26453ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26458ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26457ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26456ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26459ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26463ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26460ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26454ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26452ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26464ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26465ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26455ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26461ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26597ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26639ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26599ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:27125ADP: redhat-SADP · vendor-advisory, x_refsource_REDHAT

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