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7.5
flagd Allows Malicious Requests to Crash the Server
GHSA-rmrf-g9r3-73pm
CVE-2026-31866
Summary
The flagd server doesn't limit how much data it processes at once, which allows an attacker to send a large request and cause the server to run out of memory and shut down. This can happen without any authentication checks, making it easy for an attacker to exploit. To fix this, consider adding a limit to the amount of data flagd can process at once, and make sure to use authentication to control who can make requests to the server.
What to do
- Update github.com open-feature to version 0.14.2.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| github.com | open-feature | <= 0.14.2 | 0.14.2 |
Original title
flagd Vulnerable to Allocation of Resources Without Limits or Throttling
Original description
## Details
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.
## Impact
- **Denial of Service:** A single crafted request can crash the flagd process.
- **Service Disruption:** All applications relying on the affected flagd instance for feature flag evaluation will lose access to flag evaluations until the process restarts.
- **Repeated Exploitation:** An attacker can continuously send oversized requests to prevent recovery.
## Affected Endpoints
- `/ofrep/v1/evaluate/flags/{flagKey}` (OFREP single flag evaluation)
- `/ofrep/v1/evaluate/flags` (OFREP bulk evaluation)
- `flagd.evaluation.v1.Service/ResolveBoolean` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveString` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveFloat` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveInt` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveObject` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveAll` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveBoolean` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveString` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveFloat` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveInt` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveObject` (gRPC/Connect)
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.
## Impact
- **Denial of Service:** A single crafted request can crash the flagd process.
- **Service Disruption:** All applications relying on the affected flagd instance for feature flag evaluation will lose access to flag evaluations until the process restarts.
- **Repeated Exploitation:** An attacker can continuously send oversized requests to prevent recovery.
## Affected Endpoints
- `/ofrep/v1/evaluate/flags/{flagKey}` (OFREP single flag evaluation)
- `/ofrep/v1/evaluate/flags` (OFREP bulk evaluation)
- `flagd.evaluation.v1.Service/ResolveBoolean` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveString` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveFloat` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveInt` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveObject` (gRPC/Connect)
- `flagd.evaluation.v1.Service/ResolveAll` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveBoolean` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveString` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveFloat` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveInt` (gRPC/Connect)
- `flagd.evaluation.v2.Service/ResolveObject` (gRPC/Connect)
ghsa CVSS3.1
7.5
Vulnerability type
CWE-770
Allocation of Resources Without Limits
Published: 11 Mar 2026 · Updated: 13 Mar 2026 · First seen: 11 Mar 2026