CVE-2023-6841VulnerabilityPublished 10 Sep 2024Updated 8 Nov 2025

CVE-2023-6841: Improper Handling of Extra Values

Source 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: 0.7% chance of exploitation in 30 days – higher than 54% 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 10 Sep 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

1. Implement strict server-side limits on the number of attributes allowed per object in Keycloak requests to prevent resource exhaustion. 2. Deploy rate limiting and anomaly detection on HTTP requests targeting Keycloak endpoints to identify and block suspicious traffic patterns indicative of DoS attempts. 3. Monitor Keycloak server resource usage closely for unusual spikes in CPU or memory consumption that could signal exploitation attempts. 4. Apply any official patches or updates from the Keycloak development team as soon as they become available to address this vulnerability directly. 5. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block requests with excessive attribute counts or abnormally long attribute values. 6. Segment Keycloak infrastructure and implement redundancy to minimize service disruption in case of an attack. 7. Educate security teams to recognize signs of this specific DoS attack vector and prepare incident response plans accordingly. 8. Engage with Keycloak community or vendor support channels to stay informed about mitigation best practices and patch releases.

Description

A denial of service vulnerability was found in keycloak where the amount of attributes per object is not limited,an attacker by sending repeated HTTP requests could cause a resource exhaustion when the application send back rows with long attribute values.

Impact

For European organizations, the primary impact of CVE-2023-6841 is on the availability of Keycloak services. Keycloak often serves as a central identity provider for enterprise applications, cloud services, and government portals. A successful denial of service attack could lead to widespread authentication failures, preventing legitimate users from accessing essential services. This could disrupt business operations, cause financial losses, and damage organizational reputation. Public sector entities, financial institutions, and large enterprises that rely heavily on Keycloak for secure access management are particularly vulnerable. Additionally, prolonged outages could increase the risk of secondary security issues, such as fallback to less secure authentication methods or increased helpdesk workload. The vulnerability does not impact confidentiality or integrity directly but poses a significant operational risk. Given the remote and unauthenticated nature of the exploit, attackers can launch attacks from anywhere, increasing the threat surface for European organizations.

References

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