kafka-python prior to 2.3.2 DoS via SCRAM Iteration Count in scram.py
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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Jun 10, 2026
- Updated
- Sep 10, 2026
- EPSS
- 0.5% · 42th percentile
- CWE
- CWE-400
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Report tools
Action score
34
Monitor
Low priority for now.
- CVSS
- 34 / 40 · 8.7 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| dpkp | kafka-python | cpe:2.3:a:dpkp:kafka-python |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- dpkp kafka-pythonbefore 2.3.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.
Dana Powers kafka-python
- before 2.3.2affected · git
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | python-kafka | all versions | — |
| Debian:14 | python-kafka | before 2.0.2-12 | 2.0.2-12 |
| PyPI | kafka-python | before 2.3.2 | 2.3.2 |
Same product
dpkp: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-10142kafka-python prior to 2.3.2 Denial of Service via Protocol Parser Frame Length34Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Dana Powers kafka-python | 2.3.2 | Vendor (CNA) |
| debian:python-kafka | 2.0.2-12 · Debian:14 | Package registry (OSV) |
| PyPI:kafka-python | 2.3.2 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Katriel Mosesfinder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-400 · Uncontrolled Resource ConsumptionCVSS vector
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
nvd-secondary
Root cause
Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.
The bug in code
The whole CWE-400 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
function expand(node) { return node.children.map(expand);}Fixed
const MAX_DEPTH = 32;function expand(node, depth = 0) { if (depth > MAX_DEPTH) throw new Error("too deep"); return node.children.map((c) => expand(c, depth + 1));}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/dpkp/kafka-python/commit/6e4831444f972d169cdd11f5c8d50333cea3f19b
- github.com/dpkp/kafka-python/pull/3019
- github.com/dpkp/kafka-python/pull/3026
- www.vulncheck.com/advisories/kafka-python-prior-to-dos-via-scram-iteration-count-in-scram-py
- access.redhat.com/errata/RHSA-2026:28571
- access.redhat.com/errata/RHSA-2026:30076
- access.redhat.com/errata/RHSA-2026:33683
- access.redhat.com/errata/RHSA-2026:41066
- access.redhat.com/errata/RHSA-2026:42796
- access.redhat.com/security/cve/CVE-2026-10143
- bugzilla.redhat.com/show_bug.cgi?id=2487722
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-10143.json
Vendor advisories and official records. Exploit/PoC links are deliberately left out.