open-feature flagd up to 0.14.1 Endpoint /ofrep/v1/evaluate/ allocation of resources

Summaryinfo

A vulnerability described as problematic has been identified in open-feature flagd up to 0.14.1. The affected element is an unknown function of the file /ofrep/v1/evaluate/ of the component Endpoint. Executing a manipulation can lead to allocation of resources. This vulnerability appears as CVE-2026-31866. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic was found in open-feature flagd up to 0.14.1. This vulnerability affects an unknown code block of the file /ofrep/v1/evaluate/ of the component Endpoint. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. CVE summarizes:

flagd is a feature flag daemon with a Unix philosophy. Prior to 0.14.2, flagd exposes OFREP (/ofrep/v1/evaluate/...) and gRPC (evaluation.v1, evaluation.v2) endpoints for feature flag evaluation. These endpoints are designed to be publicly accessible by client applications. The evaluation context included in request payloads is read into memory without any size restriction. An attacker can send a single HTTP request with an arbitrarily large body, causing flagd to allocate a corresponding amount of memory. This leads to immediate memory exhaustion and process termination (e.g., OOMKill in Kubernetes environments). flagd does not natively enforce authentication on its evaluation endpoints. While operators may deploy flagd behind an authenticating reverse proxy or similar infrastructure, the endpoints themselves impose no access control by default. This vulnerability is fixed in 0.14.2.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-31866 since 03/09/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 0.14.2 eliminates this vulnerability. Applying the patch 25c5fd7e80c26eb2c00b20317b2456fe6f927ea3 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• open-feature

Name

• flagd

Version

• 0.14.0
• 0.14.1

License

• open-source

Website

• Product: https://github.com/open-feature/flagd/

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