CVE-2025-46332 is a medium-severity vulnerability affecting the Vercel Flags SDK, an open-source feature flags toolkit widely used in Next.js and SvelteKit applications. The affected versions include flags prior to 4.0.0 and @vercel/flags versions 3.1.1 and earlier. The vulnerability arises from improper access control on the flags discovery endpoint located at /.well-known/vercel/flags. Under certain conditions, an attacker with detailed knowledge of the vulnerability can query this endpoint and retrieve a comprehensive list of all feature flags exposed by the application. This list includes sensitive metadata such as flag names, descriptions, available options (e.g., true/false), labels, and default values. Such information disclosure can aid attackers in understanding application behavior, feature rollout strategies, and potentially infer sensitive business logic or upcoming features. The flaw does not require authentication or user interaction and can be exploited remotely over the network with low complexity. The vulnerability impacts confidentiality and integrity to a limited extent, as it exposes internal configuration data but does not allow direct code execution or data modification. The issue has been addressed in flags version 4.0.0, and users are strongly advised to upgrade to this patched version to mitigate the risk. No known exploits are currently reported in the wild, but the availability of detailed information could facilitate targeted attacks or social engineering efforts if left unpatched.

For European organizations, the exposure of feature flag configurations can have several implications. Feature flags often control the activation of new functionalities, experimental features, or security controls. Disclosure of these flags can enable attackers to identify unprotected or partially deployed features, potentially increasing the attack surface. In regulated sectors such as finance, healthcare, or critical infrastructure, leaking internal feature deployment details could aid adversaries in crafting sophisticated attacks or bypassing security mechanisms. Additionally, competitors or malicious insiders could leverage this information for industrial espionage or reputational damage. While the vulnerability does not directly compromise user data or system availability, the indirect risks related to business logic exposure and strategic feature rollout transparency are significant. Organizations relying on Next.js or SvelteKit frameworks with Vercel Flags SDK should consider this vulnerability a priority to address, especially those with public-facing applications or sensitive operational environments.

1. Immediate upgrade to flags SDK version 4.0.0 or later, which contains the patch for this vulnerability. 2. Review and restrict access to the /.well-known/vercel/flags endpoint by implementing network-level controls such as IP whitelisting or VPN access where feasible. 3. Employ application-layer access controls to ensure that feature flag metadata is only accessible to authorized users or internal systems. 4. Conduct an audit of all feature flags to assess sensitivity and remove or obfuscate any flags that expose critical business logic or security-related features. 5. Implement monitoring and alerting on unusual access patterns to the flags discovery endpoint to detect potential reconnaissance activities. 6. Integrate security testing into the CI/CD pipeline to detect exposure of sensitive endpoints in future releases. 7. Educate development teams on secure feature flag management and the risks of exposing internal configuration data publicly.