Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-35554 is a high-severity Race Condition (CWE-362) vulnerability in Apache Kafka. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 37th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-35554 is a race condition in the Apache Kafka Java producer client’s buffer pool management that can cause messages to be silently delivered to incorrect topics. The vulnerability occurs when a produce batch expires due to delivery.timeout.ms while its network request remains in flight, leading to premature deallocation of the batch’s ByteBuffer and its return to the buffer pool. A subsequent producer batch, potentially for a different topic, may then reuse the buffer before the original request completes, corrupting its contents and resulting in misdelivery without errors reported to the producer. It affects Apache Kafka versions ≤ 3.9.1, ≤ 4.0.1, and ≤ 4.1.1, with a CVSS score of 8.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N) and associated CWEs CWE-362 and CWE-416.
The vulnerability enables network-based exploitation by unauthenticated attackers (PR:N), though it requires high complexity (AC:H) due to precise timing of batch expiration and buffer reuse amid in-flight requests. Successful exploitation allows attackers to cause messages intended for one topic to be delivered to another, compromising data confidentiality by exposing sensitive content to consumers authorized for the destination topic but not the source. It also disrupts data integrity, as unintended recipients may face deserialization failures, processing errors, or corrupted downstream data from incompatible messages.
Apache Kafka advisories recommend upgrading to fixed versions 3.9.2, 4.0.2, 4.1.2, 4.2.0, or later to resolve the issue. Additional details are documented in the Apache JIRA ticket at https://issues.apache.org/jira/browse/KAFKA-19012, the announcement mailing list at https://lists.apache.org/thread/f07x7j8ovyqhjd1to25jsnqbm6wj01d6, and the OSS-Security list at http://www.openwall.com/lists/oss-security/2026/04/07/6.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19631
Vulnerability Data
A race condition in the Apache Kafka Java producer client’s buffer pool management can cause messages to be silently delivered to incorrect topics. When a produce batch expires due to delivery.timeout.ms while a network request containing that batch is still…
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in flight, the batch’s ByteBuffer is prematurely deallocated and returned to the buffer pool. If a subsequent producer batch—potentially destined for a different topic—reuses this freed buffer before the original network request completes, the buffer contents may become corrupted. This can result in messages being delivered to unintended topics without any error being reported to the producer. Data Confidentiality: Messages intended for one topic may be delivered to a different topic, potentially exposing sensitive data to consumers who have access to the destination topic but not the intended source topic. Data Integrity: Consumers on the receiving topic may encounter unexpected or incompatible messages, leading to deserialization failures, processing errors, and corrupted downstream data. This issue affects Apache Kafka versions ≤ 3.9.1, ≤ 4.0.1, and ≤ 4.1.1. Kafka users are advised to upgrade to 3.9.2, 4.0.2, 4.1.2, 4.2.0, or later to address this vulnerability.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 3 hardening rules · 3 OS baselines
V10.4.2V10.4.5V15.1.3V15.4.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover use-after-free bugs through dynamic analysis or fuzzing.
Engineering principles can require memory-safe constructs or languages that structurally avoid introducing use-after-free.
Maintaining separate execution domains for each process structurally eliminates unintended concurrent access to the same shared resources.
Preventing unintended information transfer through shared system resources directly addresses the improper concurrent modification that defines a race condition.
Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.
Routine patching removes known use-after-free instances after they have been introduced in released software.
Secure SDLC practices directly require proper synchronization primitives and concurrency testing that prevent race conditions.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure SDLC mandates concurrency controls and synchronization primitives that directly prevent race conditions.
Application security requirements can specify thread-safety and locking rules, but do not prescribe implementation details.
Secure architecture principles require proper synchronization and resource isolation, addressing the root cause of CWE-362.
Secure coding standards explicitly forbid unsafe concurrent access patterns and mandate atomic operations or locks.
Security testing can detect race conditions, but does not prevent them at design or coding time.
Change-management processes help ensure memory-safety fixes are deployed consistently.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
- V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
- V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416