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Vulnerability · Published Sep 15, 2026 · Assigned by GitHub_M

CVE-2026-44300OpenCost ServiceKey Endpoint Unauthorized Credential Overwrite/Injection

High 8.8

In plain English

A high-severity improper input validation in opencost from opencost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 55% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.8High
Exploit odds (30 days)0.8%top 44.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/opencost/opencost1.119.1GHSA-wmj8-9953-vff5
Gogithub.com/opencost/opencost1.119.1GO-2026-5974

Affected products (as reported)

VendorProductVersions
opencost opencost < 1.121.0

Weakness: CWE-20, CWE-309 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

References