Blnk has an API key authorization bypass in owner and scope enforcement
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- Security bypass
- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from GitHub. Impact type from CWE-863.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | github.com/blnkfinance/blnk (Go) | before 0.14.3 | 0.14.3 | Patch available | GHSA-wcr3-9x4c-f5gj |
- github.com/blnkfinance/blnk (Go) Vendor— Affected before 0.14.3 Fixed in 0.14.3 Patch available GHSA-wcr3-9x4c-f5gj
Remediation
- Fix · GHSA-wcr3-9x4c-f5gj github.com/blnkfinance/blnk (Go) Fixed in 0.14.3 Advisory →
Timeline
- 2026-10-03 Threatist record created from GHSA-wcr3-9x4c-f5gj
References
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences