CVE-2025-46332

An information disclosure vulnerability affecting Flags SDK has been addressed. It impacted flags ≤3.2.0 and @vercel/flags ≤3.1.1 and in certain circumstances, allowed a bad actor with detailed knowledge of the vulnerability to list all flags returned by the flags discovery endpoint (.well-known/vercel/flags).

Resolution

The verifyAccess function was patched within [email protected].

Users of @vercel/flags should also migrate to [email protected].

For further guidance on upgrading your version, please see our upgrade guide.

Mitigations

Vercel implemented a network-level mitigation to prevent the default flags discovery endpoint at /.well-known/vercel/flags being reachable, which automatically protects Vercel deployments against exploitation of this issue. Users need to upgrade to [email protected] to re-enable the Flags Explorer.

This automatic mitigation is not effective in two scenarios:

• When using the Flags SDK on Pages Router, as the original non-rewritten route would still be accessible, e.g. /api/vercel/flags.
• When using a custom path for the flags discovery endpoint.

If you are not protected by the Vercel default mitigation you can temporarily deny access to the other exposed flags discovery endpoints through a custom WAF rule while you upgrade to the latest version.

References

• https://vercel.com/changelog/information-disclosure-in-flags-sdk-cve-2025-46332
• https://github.com/vercel/flags/blob/main/packages/flags/guides/upgrade-to-v4.md

This vulnerability allowed for information disclosure, where a bad actor could gain access to a list of all feature flags exposed through the flags discovery endpoint, including the:

• Flag names
• Flag descriptions
• Available options and their labels (e.g. true, false)
• Default flag values

Not impacted:

• Flags providers were not accessible

No write access nor additional customer data was exposed, this is limited to just the values noted above. Vercel has automatically mitigated this incident on behalf of our customers for the default flags discovery endpoint at .well-known/vercel/flags. Flags Explorer will be disabled and show a warning notice until upgraded to [email protected].

CVE-2025-46332 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.0.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-46332? CVE-2025-46332 is a medium-severity security vulnerability in flags (npm), affecting versions <= 3.2.0. It is fixed in 4.0.0.
2. How severe is CVE-2025-46332? CVE-2025-46332 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2025-46332?
   • flags (npm) (versions <= 3.2.0)
   • @vercel/flags (npm) (versions <= 3.1.1)
4. Is there a fix for CVE-2025-46332? Yes. CVE-2025-46332 is fixed in 4.0.0. Upgrade to this version or later.
5. Is CVE-2025-46332 exploitable, and should I be worried? Whether CVE-2025-46332 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-46332 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-46332? Upgrade flags to 4.0.0 or later.