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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.52%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 4.0
- 8.7 HIGHCVSS: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/M
- EPSS
- 0.52% probability · 42th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-606
- Affected
- dpkp/kafka-python
- Source
- disclosure@vulncheck.com
References
- https://github.com/dpkp/kafka-python/commit/6e4831444f972d169cdd11f5c8d50333cea3f19bPatch
- https://github.com/dpkp/kafka-python/pull/3019Issue Tracking, Patch
- https://github.com/dpkp/kafka-python/pull/3026Issue Tracking, Patch
- https://www.vulncheck.com/advisories/kafka-python-prior-to-dos-via-scram-iteration-count-in-scram-pyPatch, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:28571
- https://access.redhat.com/errata/RHSA-2026:30076
- https://access.redhat.com/errata/RHSA-2026:33683
- https://access.redhat.com/errata/RHSA-2026:41066
- https://access.redhat.com/errata/RHSA-2026:42796
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.