How severe is CVE-2021-3637?

CVE-2021-3637 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-3637?

CVE-2021-3637 affects the following packages: org.keycloak:keycloak-model-infinispan (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-3637?

Update org.keycloak:keycloak-model-infinispan to 14.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-3637 is resolved across your whole dependency graph.

How do I detect CVE-2021-3637 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-model-infinispan, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-3637 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2021-3637 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-3637 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-3637?

CVE-2021-3637 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 66th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-3637?

CVE-2021-3637 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-3637 published, and has it been updated?

CVE-2021-3637 was published on July 9, 2021 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2021-3637 — keycloak-model-infinispan

HIGH

CVE-2021-3637 is a high-severity (CVSS 7.5) CWE-770 vulnerability in org.keycloak:keycloak-model-infinispan. A fix is available for org.keycloak:keycloak-model-infinispan — see the affected versions and patch details below.

Allocation of resources without limits or throttling in keycloak-model-infinispan

Also known asGHSA-2vp8-jv5v-6qh6

Published

Jul 9, 2021

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs66th percentile — riskier than 66% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.keycloak:keycloak-model-infinispan

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

A flaw was found in keycloak-model-infinispan in keycloak versions before 14.0.0 where authenticationSessions map in RootAuthenticationSessionEntity grows boundlessly which could lead to a DoS attack.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.keycloak:keycloak-model-infinispan`	all versions	14.0.0`org.keycloak:keycloak-model-infinispan:14.0.0`

Affected Products

2 products · 2 configurations

Application

keycloakredhat

< 14.0.0

range

Application

single sign-onredhat

1 version

7.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-model-infinispan, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.keycloak:keycloak-model-infinispan to 14.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-3637 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
Red Hat Single Sign-On 7.4.9	`keycloak-model-infinispan`	RHSA-2021:3534
Red Hat Single Sign-On 7.4 for RHEL 6	`rh-sso7-keycloak-0:9.0.15-1.redhat_00002.1.el6sso`	RHSA-2021:3527
Red Hat Single Sign-On 7.4 for RHEL 7	`rh-sso7-keycloak-0:9.0.15-1.redhat_00002.1.el7sso`	RHSA-2021:3528
Red Hat Single Sign-On 7.4 for RHEL 8	`rh-sso7-keycloak-0:9.0.15-1.redhat_00002.1.el8sso`	RHSA-2021:3529

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-3637 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

7.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

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

CWE Classification

CWE-770CWE-770

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Jul 9, 2021

Last updated

Oct 24, 2026

Identifiers

CVE-2021-3637

GHSA-2vp8-jv5v-6qh6

References

Advisorynvd.nist.gov · CVE 2021 3637 Reportbugzilla.redhat.com · show bug.cgi

Related vulnerabilities

Also affects keycloak-model-infinispan

This CVE is high severity, in line with the other 1 CVE affecting keycloak-model-infinispan.

CVE-2019-14832

Same weakness: CWE-770

This CVE is high severity; 3 of 7 other CVEs with CWE-770 are rated as high or higher (top: high).

CVE-2026-116773CVE-2026-119208CVE-2026-116775CVE-2026-116696CVE-2026-119209GHSA-vpp8-g58w-m8mpGHSA-2hw4-c9m4-f2fjBrowse all CWE-770

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026

CVE-2021-3637 — keycloak-model-infinispan

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2021-3637 in your dependencies?