This High severity Race condition vulnerability was introduced in versions 9.0.1, 9.1.0, 9.2.0, 9.3.0, 9.4.0, 9.5.0, and 9.6.0 of Bitbucket Data Center.

This Race condition vulnerability, with a CVSS Score of 8.7 and a CVSS Vector of CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N allows an unauthenticated attacker to modify code sequences in which exclusive access to shared resources is operating concurrently which has high impact to confidentiality, high impact to integrity, no impact to availability, and requires no user interaction.

Atlassian recommends that Bitbucket Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:

• Bitbucket Data Center 9.4: Upgrade to a release greater than or equal to 9.4.22

See the release notes (https://confluence.atlassian.com/bitbucketserver/release-notes). You can download the latest version of Bitbucket Data Center from the download center (https://www.atlassian.com/software/bitbucket/download-archives).

The National Vulnerability Database provides the following description for this vulnerability: 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 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.