Is CVE-2026-33557 in the CISA KEV catalog?

No. CVE-2026-33557 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-33557?

CVE-2026-33557 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2026-33557?

CVE-2026-33557 has an EPSS score of 0.58% (44th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-33557?

Upgrade kafka to 4.1.2 or later.

CVE & CISA-KEV Catalog

CVE-2026-33557

CRITICAL

9.1

CVSS v3

NVD

Description

A possible security vulnerability has been identified in Apache Kafka. By default, the broker property `sasl.oauthbearer.jwt.validator.class` is set to `org.apache.kafka.common.security.oauthbearer.DefaultJwtValidator`. It accepts any JWT token without validating its signature, issuer, or audience. An attacker can generate a JWT token from any issuer with the `preferred_username` set to any user, and the broker will accept it. We advise the Kafka users using kafka v4.1.0 or v4.1.1 to set the config `sasl.oauthbearer.jwt.validator.class` to `org.apache.kafka.common.security.oauthbearer.BrokerJwtValidator` explicitly to avoid this vulnerability. Since Kafka v4.1.2 and v4.2.0 and later, the issue is fixed and will correctly validate the JWT token.

CWE-1285 CWE-303

How to fix

Remediation Available

kafkaNVD

Affected:>= 4.1.0, < 4.1.2Fixed in:4.1.2CVE-2026-33557derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.58%probability of exploitation in 30 days

44thpercentile

Moderate risk: more likely to be exploited than 44% of all known CVEs.

References

Vendor Advisory2

Mailing List1

openwall.com

Other references3

Related Vulnerabilities

Other CWE-1285 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-46724	High	8.6	4.0%	-	Fix
CVE-2022-21821	High	7.8	2.0%	-	Fix
CVE-2026-2006	High	8.8	1.1%	-	Fix
CVE-2020-25241	High	7.5	1.0%	-	Fix
CVE-2025-3357	Critical	9.8	0.9%	-	-
CVE-2022-22223	Medium	6.5	0.8%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-15.