Bug 2487722 (CVE-2026-10143)

Summary: CVE-2026-10143 kafka-python: kafka-python: Denial of Service via excessive SCRAM authentication iteration count
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: adudiak, bdettelb, doconnor, kaycoth, kshier, stcannon, teagle, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in kafka-python. A malicious or machine-in-the-middle broker could exploit a denial-of-service vulnerability during SCRAM authentication. By providing an excessively large iteration count, the broker can cause the client's event loop to freeze. This prevents critical operations such as sending messages, polling for new messages, and maintaining heartbeats, ultimately leading to consumer group eviction and persistent connection failures.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-06-10 21:02:38 UTC 
kafka-python prior to 2.3.2 contains a denial-of-service vulnerability in SCRAM authentication handling that allows a malicious or machine-in-the-middle broker to freeze the client event loop by supplying an excessively large iteration count. In scram.py, ScramClient.process_server_first_message() passes the broker-controlled SCRAM iteration count directly to hashlib.pbkdf2_hmac() without validation, blocking producer sends, consumer polls, admin operations, and heartbeats, which can cause consumer group eviction and repeated reconnect failures.