CVE-2026-10143

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.

Score

CVSS 4.0 8.7 High

Status

Modified - disclosure@vulncheck.com

Published

2026-06-10

Last modified

2026-10-08

Weaknesses

CWE-400, CWE-606

Affected products

• Kafka-python (Dpkp)
• Quay (Redhat)

References

• https://github.com/dpkp/kafka-python/pull/3019
• https://github.com/dpkp/kafka-python/commit/6e4831444f972d169cdd11f5c8d50333cea3f19b
• https://github.com/dpkp/kafka-python/pull/3026
• https://www.vulncheck.com/advisories/kafka-python-prior-to-dos-via-scram-iteration-count-in-scram-py
• https://access.redhat.com/security/cve/CVE-2026-10143
• https://bugzilla.redhat.com/show_bug.cgi?id=2487722
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-10143.json
• https://access.redhat.com/errata/RHSA-2026:33683
• https://access.redhat.com/errata/RHSA-2026:30076
• https://access.redhat.com/errata/RHSA-2026:42796
• https://access.redhat.com/errata/RHSA-2026:41066
• https://access.redhat.com/errata/RHSA-2026:28571