VulnerabilityPublished 28 Oct 2026

CVE-2026-110985: Apache Kafka · Insufficient Verification of Data Authenticity

Affects Apache KafkaSource CVE Database V5

Mentioned vulnerabilities

CVE-2026-33557

Not known to be exploited · fixed in 4.2.2 : patch Apache Kafka soon.

Data as of 28 Oct 2026, 17:22 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in 4.2.2

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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
Apache Kafkaorg.apache.kafka:kafka	Affected >=4.1.0 <=4.1.2 >=4.2.0 <=4.2.1 =4.3.0	Fixed in–
MavenApache Software Foundation/org.apache.kafka:kafka`pkg:maven/Apache Software Foundation/org.apache.kafka:kafka`Other threats	Affected >=4.1.0 <=4.1.2 >=4.2.0 <=4.2.1 =4.3.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability on all affected versions without upgrading, administrators must configure the sasl.oauthbearer.jwks.endpoint.url parameter for every listener and mechanism using OAuthBearerValidatorCallbackHandler, or alternatively configure a signature-verifying sasl.oauthbearer.jwt.validator.class. Upgrading to Apache Kafka versions 4.2.2, 4.3.1, or 4.4.0 is recommended, as these versions prevent brokers from starting if signature verification is not properly configured, enforcing secure defaults.

Description

CVE-2026-110985 is a vulnerability in Apache Kafka brokers using SASL/OAUTHBEARER authentication with the default JWT validator. If the configuration parameter sasl.oauthbearer.jwks.endpoint.url is not set and no custom verification key resolver is provided, the broker falls back to a validator that does not verify JWT signatures, algorithms, or issuers. This allows an unauthenticated remote attacker to forge any JWT token, including those asserting superuser privileges, gaining full cluster access. The issue affects specific Kafka versions prior to fixed releases. The vulnerability is resolved in Apache Kafka versions 4.2.2, 4.3.1, and 4.4.0, where the broker fails to start if signature verification is not properly configured.

Impact

The vulnerability allows an unauthenticated remote attacker who can reach the Kafka listener to forge JWT tokens without signature verification. This enables the attacker to impersonate any principal, including superusers, resulting in full unauthorized access to the Kafka cluster. Only brokers that enable SASL/OAUTHBEARER validation without setting the JWKS endpoint URL and without a custom verification key resolver are affected. Brokers with the JWKS endpoint URL set verify signatures and are not vulnerable. This represents a critical security risk due to the potential for complete cluster compromise.

CWE-345Insufficient Verification of Data Authenticity (opens in a new tab)
Class weaknessOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cache Poisoning (opens in a new tab)
DNS Cache Poisoning (opens in a new tab)
Spoofing of UDDI/ebXML Messages (opens in a new tab)
Application API Message Manipulation via Man-in-the-Middle (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-347Improper Verification of Cryptographic Signature (opens in a new tab)
Base weaknessOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
Padding Oracle Crypto Attack (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-1287Improper Validation of Specified Type of Input (opens in a new tab)
Base weakness
The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-636Not Failing Securely ('Failing Open') (opens in a new tab)
Class weaknessOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.
Architecture and Design
Subdivide and allocate resources and components so that a failure in one part does not affect the entire product.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

kafka.apache.org/cve-list (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 17:06 UTC

WeaknessesCWE-345, CWE-347, CWE-1287 +1

Technical details

References

Community reviews

Related threats