VulnerabilityPublished 18 Mar 2026Updated 6 Oct 2026

CVE-2026-2575: Red Hat build of Keycloak 26.4 · Data Amplification

Affects Red Hat build of Keycloak 26.4Source CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium.

Data as of 31 Oct 2026, 08:20 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 51% 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:L

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

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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity 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

Affected software

Product	Affected	Fixed in
Red HatRed Hat build of Keycloak 26.4	Affected–	Fixed in–
Red HatRed Hat build of Keycloak 26.4	Affected–	Fixed in–
Red HatRed Hat build of Keycloak 26.4.10	Affected–	Fixed in–
Red HatRed Hat Single Sign-On 7.6.13	Affected–	Fixed in–
Red HatRed Hat Single Sign-On 7.6 for RHEL 7	Affected–	Fixed in–
Red HatRed Hat Single Sign-On 7.6 for RHEL 8	Affected–	Fixed in–

AI-suggested

To mitigate CVE-2026-2575, organizations should first monitor Red Hat and Keycloak vendor advisories for official patches or updates addressing this vulnerability and apply them promptly. In the absence of patches, implement strict input validation and size limits on incoming SAMLRequests at the application or reverse proxy level to prevent processing of excessively large or suspicious payloads. Configure network-level protections such as Web Application Firewalls (WAFs) to detect and block anomalous SAMLRequest traffic patterns indicative of compression bombs or data amplification attacks. Employ resource limits and monitoring on Keycloak servers to detect and respond to abnormal memory usage spikes. Consider isolating Keycloak instances behind hardened gateways that can enforce protocol compliance and rate limiting. Regularly audit and review authentication logs for unusual activity. Additionally, ensure that Keycloak runs with appropriate Java Virtual Machine (JVM) memory settings and consider enabling JVM options that limit decompression resource consumption. Educate security teams about this vulnerability to improve detection and incident response readiness. Avoid exposing Keycloak endpoints unnecessarily to untrusted networks.

Description

A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.

Impact

The primary impact of CVE-2026-2575 is the disruption of availability of Keycloak authentication services. Organizations relying on Keycloak 26.4 for identity and access management may experience service outages if targeted by this attack, potentially preventing users from authenticating or accessing critical applications. This can lead to operational downtime, loss of productivity, and potential cascading effects on dependent systems. Since the vulnerability does not affect confidentiality or integrity, data breaches or unauthorized access are not direct concerns. However, denial of service on authentication infrastructure can indirectly increase risk by forcing fallback to less secure methods or causing operational chaos. The ease of exploitation without authentication or user interaction increases the likelihood of opportunistic attacks, especially in exposed environments. Large enterprises, government agencies, and cloud service providers using Keycloak are particularly at risk. The absence of known exploits in the wild currently limits immediate impact but does not preclude future exploitation. Overall, the vulnerability poses a moderate risk to service continuity and operational stability.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 18 Mar 2026, 14:28 UTC

Technical details

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