CVE-2026-54775: CoreWCF: Kafka consume pump halts permanently on a Kafka tombstone (null-value record), causing persistent endpoint denial of service.

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-08 · updated 2026-07-09
Weakness: CWE-248

Description

CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, a CoreWCF service listening on a Kafka topic stops processing new records from that topic when KafkaTransportPump receives a null-value tombstone record, causing a persistent endpoint denial of service for attackers with produce permission. This issue is fixed in versions 1.8.1 and 1.9.1.

Affected products

CoreWCF: from 1.9.0, < 1.9.1; before 1.8.1

References

https://github.com/CoreWCF/CoreWCF/commit/1a229d0d14a07766302f7d14c866889f04a3a624
https://github.com/CoreWCF/CoreWCF/commit/6d7431ebc0ebe6521ea6d0dbea8982bac3d2bc98
https://github.com/CoreWCF/CoreWCF/commit/8f95f3ac3c929409e830b5c5659683ef9f6ea6b0
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1
https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1
https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-m744-jhq9-ppw6

Get alerted when CVE-2026-54775 or the next vulnerability affects your stack