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MEDIUM severity

GHSA-7f4h-6264-89fr axonflow

MEDIUM

GHSA-7f4h-6264-89fr is a medium-severity (CVSS 5.9) vulnerability in axonflow. A fix is available for axonflow — see the affected versions and patch details below.

axonflow-sdk-python: Webhook signing-key (HMAC-SHA256) not exposed by SDK type, preventing signature verification

Published
May 6, 2026
Updated
May 6, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of May 6, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🐍axonflow

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIaxonflowall versions6.7.0pip install --upgrade 'axonflow==6.7.0'

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for axonflow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update axonflow to 6.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7f4h-6264-89fr is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-7f4h-6264-89fr can be triaged on real exposure rather than presence alone.

Tailored to GHSA-7f4h-6264-89fr. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## 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 fi
O3 Security · Impact-Aware SCA

Is GHSA-7f4h-6264-89fr in your dependencies?

O3 Security finds GHSA-7f4h-6264-89fr across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-7f4h-6264-89fr: axonflow (Medium 5.9) | O3 Security