How severe is GHSA-mhc4-qq83-fmrr?

GHSA-mhc4-qq83-fmrr has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-mhc4-qq83-fmrr?

GHSA-mhc4-qq83-fmrr affects the following packages: github.com/getaxonflow/axonflow-sdk-go/v5 (Go). Ecosystems affected: Go.

How do I fix GHSA-mhc4-qq83-fmrr?

Update github.com/getaxonflow/axonflow-sdk-go/v5 to 5.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mhc4-qq83-fmrr is resolved across your whole dependency graph.

How do I detect GHSA-mhc4-qq83-fmrr in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/getaxonflow/axonflow-sdk-go/v5, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-mhc4-qq83-fmrr if there is no patch (or I can't update yet)?

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.

How does O3 Security protect against GHSA-mhc4-qq83-fmrr?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-mhc4-qq83-fmrr can be triaged on real exposure rather than presence alone.

Is GHSA-mhc4-qq83-fmrr actively exploited in the wild?

No public exploit code has been indexed for GHSA-mhc4-qq83-fmrr yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-mhc4-qq83-fmrr published, and has it been updated?

GHSA-mhc4-qq83-fmrr was published on May 6, 2026 and was last updated on June 25, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

GHSA-mhc4-qq83-fmrr — v5

MEDIUM

GHSA-mhc4-qq83-fmrr is a medium-severity (CVSS 5.9) vulnerability in github.com/getaxonflow/axonflow-sdk-go/v5. A fix is available for github.com/getaxonflow/axonflow-sdk-go/v5 — see the affected versions and patch details below.

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

Also known asGO-2026-5508

Published

May 6, 2026

Updated

Jun 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Jun 25, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐹github.com/getaxonflow/axonflow-sdk-go/v5

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go 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:

Skip signature verification entirely — accepting any payload from any source that knew the webhook URL.
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 5.6.1 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:

Persist the secret returned by CreateWebhook securely (it is only returned once, at create time).
On each incoming webhook delivery, compute HMAC-SHA256(secret, raw_body) and compare it in constant time against the X-AxonFlow-Signature header.
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

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/getaxonflow/axonflow-sdk-go/v5`	all versions	5.7.0`go get github.com/getaxonflow/axonflow-sdk-go/v5@v5.7.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/getaxonflow/axonflow-sdk-go/v5, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/getaxonflow/axonflow-sdk-go/v5 to 5.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mhc4-qq83-fmrr is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-mhc4-qq83-fmrr can be triaged on real exposure rather than presence alone.

Tailored to GHSA-mhc4-qq83-fmrr. 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-mhc4-qq83-fmrr in your dependencies?

O3 Security finds GHSA-mhc4-qq83-fmrr across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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