CVE-2024-3657VulnerabilityPublished 28 May 2024Updated 25 Feb 2026

CVE-2024-3657: Red Hat Directory Server 11.5 E4S for RHEL 8 · Improper Input Validation

Affects Red Hat Directory Server 11.5 E4S for RHEL 8Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.2% chance of exploitation in 30 days – higher than 69% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 May 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

Organizations should prioritize applying official patches from Red Hat as soon as they become available to remediate this vulnerability. Until patches are released, network-level mitigations should be implemented, including restricting access to the LDAP service to trusted hosts and networks via firewalls or access control lists. Deploying intrusion detection or prevention systems (IDS/IPS) with signatures to detect anomalous or malformed LDAP queries may help identify exploitation attempts. Monitoring directory server logs for unusual query patterns or failures can provide early warning signs. Additionally, organizations should review and harden LDAP query handling configurations to limit exposure. Employing rate limiting on LDAP queries can reduce the impact of potential DoS attempts. Regular backups and high availability configurations for directory services can mitigate operational impact in case of service disruption. Finally, maintaining up-to-date threat intelligence and vendor advisories will ensure timely response to emerging exploits or patches.

Description

A flaw was found in 389-ds-base. A specially-crafted LDAP query can potentially cause a failure on the directory server, leading to a denial of service

Impact

The primary impact of CVE-2024-3657 is a denial of service condition on Red Hat Directory Server, which can cause service outages for directory and authentication services. This disruption can cascade to dependent applications and systems relying on centralized authentication, potentially halting business operations, user access, and automated workflows. Since the vulnerability does not affect confidentiality or integrity, data breaches or unauthorized data modifications are not expected. However, the loss of availability in critical directory services can severely impact organizations, especially those with large-scale deployments or those in regulated industries requiring high uptime. The ease of remote exploitation without authentication increases the risk of automated attacks or scanning by threat actors. Organizations with internet-facing directory services or insufficient network segmentation are particularly vulnerable. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as proof-of-concept exploits could emerge rapidly after disclosure.

Summary

CVE-2024-3657 identifies a vulnerability in the 389-ds-base component of Red Hat Directory Server version 11.5 E4S running on Red Hat Enterprise Linux 8. The flaw arises from improper input validation of LDAP queries, allowing an attacker to craft a malicious LDAP request that causes the directory server to fail, leading to a denial of service (DoS). This vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS v3.1 base score of 7.5 reflects a high severity due to the ease of exploitation (network vector, low attack complexity) and the impact on availability, although confidentiality and integrity remain unaffected. The directory server is a critical component in many enterprise environments, providing centralized authentication and directory services. A DoS on this server can disrupt authentication processes, access to resources, and other dependent services. While no public exploits have been reported yet, the vulnerability's nature and the widespread use of Red Hat Directory Server in enterprise and government environments make it a significant concern. The vulnerability was reserved in April 2024 and published in May 2024, indicating recent discovery and disclosure. No specific patches or workarounds are listed yet, so organizations must monitor Red Hat advisories closely. The vulnerability affects Red Hat Directory Server 11.5 E4S on RHEL 8, a platform widely used in enterprise Linux deployments.

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What to do

Description

AI analysisMachine-generated, updated 27 Feb 2026, 09:24 UTC

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