CVE-2026-44300 OpenCost ServiceKey Endpoint Unauthorized Credential Overwrite/Injection
Unauthenticated attackers can overwrite GCP service account credentials in OpenCost, potentially hijacking cloud cost collection or causing service disruption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44300?
CVE-2026-44300 is a high-severity missing authorization vulnerability in opencost, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
OpenCost provides cost monitoring for Kubernetes workloads and cloud costs. Prior to 1.121.0, the POST /serviceKey endpoint in pkg/costmodel/router.go allows a network client to invoke AddServiceKey without mandatory authentication and submit an arbitrary key form value that is written to the GCP service-account key.json file returned by GetGCPAuthSecretFilePath in core/pkg/env/core.go. The attacker controls the file contents but not the CONFIG_PATH-derived directory, the key.json filename, or the file mode. Replacing the credential contents can disrupt GCP cost collection or cause OpenCost to use attacker-selected credentials, and the wildcard Access-Control-Allow-Origin response permits browser-assisted requests when the service is reachable from a browser. This issue is fixed in version 1.121.0.
Which versions are affected by CVE-2026-44300?
3 open source packages ship an affected version, including github.com/opencost/opencost.
| Package | Affected | Fixed in |
|---|---|---|
github.com/opencost/opencost Go | All versions | 1.119.1 |
github.com/opencost/opencost Go | All versions | 1.119.1 |
github.com/opencost/opencost Go | All versions | 1.119.1 |
How do I fix CVE-2026-44300?
Upgrade github.com/opencost/opencost to 1.119.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-44300 being exploited?
There is no known exploitation of CVE-2026-44300 in the wild and no public exploit code.
Sources
Also known as GHSA-wmj8-9953-vff5, GO-2026-5974.