# GHSA-wcr3-9x4c-f5gj: Blnk has an API key authorization bypass in owner and scope enforcement

> Non-master API keys can bypass authorization to manage other owners' keys or escalate privileges by creating keys with broader scopes.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2026
- **Also known as:** GO-2026-5823

## What is GHSA-wcr3-9x4c-f5gj?

GHSA-wcr3-9x4c-f5gj is a missing authorization vulnerability in github.com/blnkfinance/blnk, published on 26 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Blnk API key endpoints had an authorization issue that allowed non-master API keys to perform key-management actions outside their intended authorization boundary.

In affected versions, API key operations trusted caller-controlled request values for owner and scope decisions. As a result, a non-master API key could potentially manage keys for another owner by supplying a different owner value, or create a more privileged API key by requesting broader scopes than it already had.

This has been fixed by deriving the effective owner from the authenticated API key and enforcing scope coverage checks when creating new keys.

## Details

The API key authorization flow previously trusted request data supplied by the caller when deciding which owner a key-management operation applied to and which scopes could be granted.

This meant a non-master API key could potentially:

- create API keys for another owner
- list API keys belonging to another owner
- revoke API keys belonging to another owner
- create a new API key with broader scopes than the caller’s own scopes

The patched version changes this behavior for non-master API keys:

- the effective owner is derived from the authenticated API key
- caller-supplied owner values are no longer trusted for authorization decisions
- cross-owner key operations are rejected with `403 Forbidden`
- requested scopes must be covered by the caller’s existing scopes
- master-key behavior is unchanged

## Impact

A non-master API key with access to API key management endpoints could potentially perform unauthorized key-management operations across owners or escalate its permissions by creating a new API key with broader scopes.

Deployments using API keys for programmatic key creation, listing, or revocation should upgrade.

## Affected versions

Versions up to and including `v0.14.2` are affected.

## Patched versions

This issue is fixed in `v0.14.3`.

Users should upgrade to `v0.14.3` or later.

## Workarounds

If developers cannot upgrade their applications immediately, restrict access to API key management endpoints to trusted master keys only.

Where possible, disable or block non-master API key access to key creation, listing, and revocation endpoints until the patched version is deployed.

## Credits

Blank thanks @Shivam8584 for identifying and fixing this issue.

## Which versions are affected by GHSA-wcr3-9x4c-f5gj?

3 open source packages ship an affected version, including github.com/blnkfinance/blnk.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/blnkfinance/blnk` | Go | All versions | 0.14.3 |
| `github.com/blnkfinance/blnk` | Go | All versions | 0.14.3 |
| `github.com/blnkfinance/blnk` | Go | All versions | 0.14.3 |

## How do I fix GHSA-wcr3-9x4c-f5gj?

Upgrade github.com/blnkfinance/blnk to 0.14.3 or later.

## Is GHSA-wcr3-9x4c-f5gj being exploited?

There is no known exploitation of GHSA-wcr3-9x4c-f5gj in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-wcr3-9x4c-f5gj and fix it if it is affected.

What it is: GHSA-wcr3-9x4c-f5gj is a missing authorization vulnerability in github.com/blnkfinance/blnk, published on 26 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-wcr3-9x4c-f5gj in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/blnkfinance/blnk (Go): affected all versions; fixed in 0.14.3
- github.com/blnkfinance/blnk (Go): affected all versions; fixed in 0.14.3
- github.com/blnkfinance/blnk (Go): affected all versions; fixed in 0.14.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-wcr3-9x4c-f5gj/ (Markdown: https://insights.sbomify.com/GHSA-wcr3-9x4c-f5gj/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-wcr3-9x4c-f5gj

---
From sbomify Insights: https://insights.sbomify.com/GHSA-wcr3-9x4c-f5gj/
Summaries are generated and may contain mistakes; the official description above is the record.