GHSA-7f4h-6264-89fr: axonflow-sdk-python Webhook Signing-key (HMAC-SHA256) Not Exposed Vulnerability

MODERATE
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CVSS 5.9
CWE-345 CWE-347
Published
Advisory Summary

GHSA-7f4h-6264-89fr is a MODERATE (CVSS 5.9) webhook signing-key (hmac-sha256) not exposed vulnerability (CWE-345: Insufficient Verification of Data Authenticity) affecting axonflow-sdk-python libraries in the PyPI ecosystem. The issue involves webhook signing-key (hmac-sha256) not exposed by sdk type, preventing signature verification. Remediation is available by upgrading affected packages to version 6.7.0.

GHSA-7f4h-6264-89fr at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-7f4h-6264-89fr
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-345: Insufficient Verification of Data Authenticity
Affected Product axonflow-sdk-python
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix GHSA-7f4h-6264-89fr

To remediate this vulnerability, upgrade all affected axonflow-sdk-python dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

axonflow fixed: 6.7.0 
pip install axonflow>=6.7.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show axonflow

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-7f4h-6264-89fr, inspect your installed packages using pip:

pip show axonflow

Analyze the terminal output to locate any version of axonflow-sdk-python in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.7.0), your application is affected.

Note: The pip show axonflow command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-345: Insufficient Verification of Data Authenticity, where the product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. In axonflow-sdk-python, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary The AxonFlow SDK's `WebhookSubscription` (or equivalent) type did not expose the HMAC-SHA256 signing key returned by the platform's `CreateWebhook` endpoint. Without access to the secret through the typed SDK API, callers had no path to verify the `X-AxonFlow-Signature` header on incoming webhook deliveries. Affected callers had two unsatisfactory options: 1. Skip signature verification entirely — accepting any payload from any source that knew the webhook URL. 2. Hand-parse the raw HTTP JSON response to extract the secret, bypassing the type-safe SDK surface. This advisory is filed across all four AxonFlow SDKs (Go, Python, TypeScript, Java) because the same defect and the same fix landed in each. ## Affected versions Versions 6.6.2 and below. ## Impact A webhook receiver using the SDK's typed API to handle inbound deliveries had no path to authenticate the source of incoming payloads. An attacker who learned the webhook URL — through misconfiguration, log leakage, observable network traffic during setup, or any other discovery channel — could forge webhook deliveries indistinguishable from legitimate ones, causing the receiving application to act on fabricated events (e.g. simulated approval-granted callbacks, simulated policy-decision callbacks, simulated step-completion callbacks). ## Remediation Upgrade to the patched version listed in Vulnerabilities below. The signing key is now exposed on the `WebhookSubscription` response type returned by `CreateWebhook`. Implementations should: 1. Persist the secret returned by `CreateWebhook` securely (it is only returned once, at create time). 2. On each incoming webhook delivery, compute `HMAC-SHA256(secret, raw_body)` and compare it in constant time against the `X-AxonFlow-Signature` header. 3. Reject any delivery whose signature does not match. ## Credit Identified by AxonFlow internal security review during the April 2026 quality-freeze epic.

GHSA-7f4h-6264-89fr Affected axonflow-sdk-python Versions

1 component(s)
Fixed Versions:
6.7.0
Product / Package Ecosystem Affected Versions Fixed Version
axonflow
pypi/axonflow
PyPI
< 6.7.0
6.7.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/getaxonflow/axonflow-sdk-python/security/advisories/GHSA-7f4h-6264-89fr
axonflow-sdk-python Source Repository REPOSITORY
https://github.com/getaxonflow/axonflow-sdk-python

Frequently Asked Questions

What is GHSA-7f4h-6264-89fr?
GHSA-7f4h-6264-89fr is a security vulnerability in axonflow-sdk-python involving Webhook signing-key (HMAC-SHA256) not exposed by SDK type, preventing signature verification under CWE-345: Insufficient Verification of Data Authenticity.
Which axonflow-sdk-python versions are affected?
Affected versions include releases prior to 6.7.0 across affected packages: axonflow.
What version fixes GHSA-7f4h-6264-89fr?
Upgrading to 6.7.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is axonflow affected?
Yes, axonflow is affected in releases prior to 6.7.0. Upgrade your dependency to 6.7.0 or later.
What is the CVSS score of GHSA-7f4h-6264-89fr?
GHSA-7f4h-6264-89fr has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with GHSA-7f4h-6264-89fr?
GHSA-7f4h-6264-89fr is classified under CWE-345: Insufficient Verification of Data Authenticity (The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.).
How can I check PyPI dependencies for GHSA-7f4h-6264-89fr?
Run the dependency tree command: 'pip show axonflow'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-7f4h-6264-89fr",
  "modified" : "2026-05-06T23:14:43Z",
  "published" : "2026-05-06T23:14:43Z",
  "aliases" : [ ],
  "summary" : "axonflow-sdk-python: Webhook signing-key (HMAC-SHA256) not exposed by SDK type, preventing signature verification",
  "details" : "## Summary\n\nThe AxonFlow SDK's `WebhookSubscription` (or equivalent) type did not expose the HMAC-SHA256 signing key returned by the platform's `CreateWebhook` endpoint. Without access to the secret through the typed SDK API, callers had no path to verify the `X-AxonFlow-Signature` header on incoming webhook deliveries. Affected callers had two unsatisfactory options:\n\n1. Skip signature verification entirely — accepting any payload from any source that knew the webhook URL.\n2. Hand-parse the raw HTTP JSON response to extract the secret, bypassing the type-safe SDK surface.\n\nThis advisory is filed across all four AxonFlow SDKs (Go, Python, TypeScript, Java) because the same defect and the same fix landed in each.\n\n## Affected versions\n\nVersions 6.6.2 and below.\n\n## Impact\n\nA webhook receiver using the SDK's typed API to handle inbound deliveries had no path to authenticate the source of incoming payloads. An attacker who learned the webhook URL — through misconfiguration, log leakage, observable network traffic during setup, or any other discovery channel — could forge webhook deliveries indistinguishable from legitimate ones, causing the receiving application to act on fabricated events (e.g. simulated approval-granted callbacks, simulated policy-decision callbacks, simulated step-completion callbacks).\n\n## Remediation\n\nUpgrade to the patched version listed in Vulnerabilities below. The signing key is now exposed on the `WebhookSubscription` response type returned by `CreateWebhook`. Implementations should:\n\n1. Persist the secret returned by `CreateWebhook` securely (it is only returned once, at create time).\n2. On each incoming webhook delivery, compute `HMAC-SHA256(secret, raw_body)` and compare it in constant time against the `X-AxonFlow-Signature` header.\n3. Reject any delivery whose signature does not match.\n\n## Credit\n\nIdentified by AxonFlow internal security review during the April 2026 quality-freeze epic.",
  "severity" : [ {
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    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"
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  } ],
  "database_specific" : {
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    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-06T23:14:43Z",
    "nvd_published_at" : null
  }
}