Apache Kafka: Deserialization of Untrusted Data
CVE-2025-27819 is a high-severity deserialization of untrusted data vulnerability in Apache Kafka from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Kafka versions: 2.0.0 through 3.3.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.11% chance of exploitation within 30 days, higher than 66% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Apache Kafka you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on kafka.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Kafka | 2.0.0 through 3.3.2 | Not stated |
| Apache | Kafka | 2.0.0 through 3.3.2 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).
Official description
In CVE-2023-25194, we announced the RCE/Denial of service attack via SASL JAAS JndiLoginModule configuration in Kafka Connect API. But not only Kafka Connect API is vulnerable to this attack, the Apache Kafka brokers also have this vulnerability. To exploit this vulnerability, the attacker needs to be able to connect to the Kafka cluster and have the AlterConfigs permission on the cluster resource. Since Apache Kafka 3.4.0, we have added a system property ("-Dorg.apache.kafka.disallowed.login.modules") to disable the problematic login modules usage in SASL JAAS configuration. Also by default "com.sun.security.auth.module.JndiLoginModule" is disabled in Apache Kafka 3.4.0, and "com.sun.security.auth.module.JndiLoginModule,com.sun.security.auth.module.LdapLoginModule" is disabled by default in in Apache Kafka 3.9.1/4.0.0
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Apache Kafka
- 8.1 High severity
- 8.8 High severity
- 7.5 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Spotted an error? Tell us.