---
id: CVE-2026-10143
title: kafka-python prior to 2.3.2 DoS via SCRAM Iteration Count in scram.py
summary: >-
  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 c…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-400
  - CWE-606
vendor: Dana Powers
product: kafka-python
affected:
  - kafka-python < 2.3.2
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-06-11T13:10:04.299411Z'
published: '2026-06-10'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T12:04:54.248Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-10143'
references:
  - url: 'https://github.com/dpkp/kafka-python/pull/3019'
  - url: >-
      https://github.com/dpkp/kafka-python/commit/6e4831444f972d169cdd11f5c8d50333cea3f19b
  - url: 'https://github.com/dpkp/kafka-python/pull/3026'
  - url: >-
      https://www.vulncheck.com/advisories/kafka-python-prior-to-dos-via-scram-iteration-count-in-scram-py
  - url: 'https://access.redhat.com/security/cve/CVE-2026-10143'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-10143.json
  - url: 'https://access.redhat.com/errata/RHSA-2026:28571'
  - url: 'https://access.redhat.com/errata/RHSA-2026:30076'
  - url: 'https://access.redhat.com/errata/RHSA-2026:33683'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2487722'
  - url: 'https://github.com/advisories/GHSA-2jcm-hq8r-84wx'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-10143'
  - url: >-
      https://github.com/dpkp/kafka-python/commit/74400d7ef1b54ad24d4b8170c23b58d1cab65e4f
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/kafka-python/PYSEC-2026-2191.yaml
  - url: 'https://github.com/dpkp/kafka-python/releases/tag/2.3.2'
  - url: 'https://github.com/dpkp/kafka-python'
  - url: 'https://access.redhat.com/errata/RHSA-2026:42796'
  - url: 'https://access.redhat.com/errata/RHSA-2026:41066'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-10143'
tags:
  - cve.org
  - osv
  - pip
  - csaf
  - vex
  - red-hat
  - nvd
epss: 0.00517
epssPercentile: 0.42825
aliases:
  - PYSEC-2026-2191
  - GHSA-2jcm-hq8r-84wx
ecosystem: pip
patched:
  - kafka-python 2.3.2
ingestedAt: '2026-07-13T18:58:07.955Z'
---

## Overview

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.

## Affected

- `kafka-python < 2.3.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-10143)

Affected packages:

- `kafka-python < 2.3.2`

Patched in:

- `kafka-python 2.3.2`

Source: https://osv.dev/vulnerability/PYSEC-2026-2191

## Vendor advisories

- **RHSA-2026:33683** · Red Hat · fixed in: Red Hat Quay 3.10 · released 2026-06-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:33683)
- **RHSA-2026:30076** · Red Hat · fixed in: Red Hat Quay 3.12 · released 2026-06-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:30076)
- **RHSA-2026:42796** · Red Hat · fixed in: Red Hat Quay 3.15 · released 2026-07-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:42796)
- **RHSA-2026:41066** · Red Hat · fixed in: Red Hat Quay 3.16 · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:41066)
- **RHSA-2026:28571** · Red Hat · fixed in: Red Hat Quay 3.9 · released 2026-06-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:28571)