PYSEC-2026-2191

Vulnerability from pysec - Published: 2026-06-10 22:16 - Updated: 2026-07-13 05:49
VLAI
Details

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.

Severity
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Impacted products
Name purl
kafka-python pkg:pypi/kafka-python
Aliases
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "PyPI",
        "name": "kafka-python",
        "purl": "pkg:pypi/kafka-python"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.0",
        "0.9.1",
        "0.9.2",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "1.0.0",
        "1.0.1",
        "1.0.2",
        "1.1.0",
        "1.1.1",
        "1.2.0",
        "1.2.1",
        "1.2.2",
        "1.2.3",
        "1.2.4",
        "1.2.5",
        "1.3.0",
        "1.3.1",
        "1.3.2",
        "1.3.3",
        "1.3.4",
        "1.3.5",
        "1.4.0",
        "1.4.1",
        "1.4.2",
        "1.4.3",
        "1.4.4",
        "1.4.5",
        "1.4.6",
        "1.4.7",
        "2.0.0",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.0.4",
        "2.0.5",
        "2.0.6",
        "2.1.0",
        "2.1.1",
        "2.1.2",
        "2.1.3",
        "2.1.4",
        "2.1.5",
        "2.1.6",
        "2.2.0",
        "2.2.1",
        "2.2.10",
        "2.2.11",
        "2.2.12",
        "2.2.13",
        "2.2.14",
        "2.2.15",
        "2.2.16",
        "2.2.17",
        "2.2.18",
        "2.2.19",
        "2.2.2",
        "2.2.20",
        "2.2.3",
        "2.2.4",
        "2.2.5",
        "2.2.6",
        "2.2.7",
        "2.2.8",
        "2.2.9",
        "2.3.0",
        "2.3.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-10143"
  ],
  "details": "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.",
  "id": "PYSEC-2026-2191",
  "modified": "2026-07-13T05:49:18.525020Z",
  "published": "2026-06-10T22:16:55.503Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-10143"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-10143.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:28571"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30076"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33683"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2487722"
    },
    {
      "type": "FIX",
      "url": "https://github.com/dpkp/kafka-python/commit/6e4831444f972d169cdd11f5c8d50333cea3f19b"
    },
    {
      "type": "FIX",
      "url": "https://github.com/dpkp/kafka-python/pull/3019"
    },
    {
      "type": "FIX",
      "url": "https://github.com/dpkp/kafka-python/pull/3026"
    },
    {
      "type": "FIX",
      "url": "https://www.vulncheck.com/advisories/kafka-python-prior-to-dos-via-scram-iteration-count-in-scram-py"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}



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