Red Hat Directory Server 11.5 E4S for RHEL 8: Allocation of Resources Without Limits or Throttling
CVE-2026-9064 is a high-severity allocation of resources without limits or throttling vulnerability in Red Hat Directory Server 11.5 E4S for RHEL 8 from Red Hat, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.81% chance of exploitation within 30 days, higher than 58% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat Directory Server 11.5 E4S for RHEL 8 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on access.redhat.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 1 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (redhat.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.5 | High | CNA |
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Allocation of Resources Without Limits or Throttling
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
How developers prevent this class of flaw
- Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
- Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Allocation of Resources Without Limits or Throttling vulnerabilities (CWE-770)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- access.redhat.com/security/cve/CVE-2026-9064Mitigation
- bugzilla.redhat.com/show_bug.cgi?id=2480093Issue Tracking
Other references
- access.redhat.com/errata/RHSA-2026:26452
- access.redhat.com/errata/RHSA-2026:26453
- access.redhat.com/errata/RHSA-2026:26454
- access.redhat.com/errata/RHSA-2026:26455
- access.redhat.com/errata/RHSA-2026:26456
- access.redhat.com/errata/RHSA-2026:26457
- access.redhat.com/errata/RHSA-2026:26458
- access.redhat.com/errata/RHSA-2026:26459
- access.redhat.com/errata/RHSA-2026:26460
- access.redhat.com/errata/RHSA-2026:26461
- access.redhat.com/errata/RHSA-2026:26463
- access.redhat.com/errata/RHSA-2026:26464
- access.redhat.com/errata/RHSA-2026:26465
- access.redhat.com/errata/RHSA-2026:26597
- access.redhat.com/errata/RHSA-2026:26599
Other vulnerabilities in Red Hat Directory Server 11.5 E4S for RHEL 8
- 8.4 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Allocation of Resources Without Limits or Throttling vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.2 High severity
- 7.5 High severity
- 8.2 High severity
- 7.5 High severity
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