OpenNext Cloudflare: Cache interception can bypass middleware protection for encoded paths

Why it is Yellow

• CVSS 7.5 high
• Remotely exploitable without logging in
• On your watchlist: npm

Affected packages

References

• https://github.com/advisories/GHSA-2vc4-c4r6-p6v6
• https://github.com/opennextjs/opennextjs-cloudflare/security/advisories/GHSA-2vc4-c4r6-p6v6
• https://nvd.nist.gov/vuln/detail/CVE-2026-100409
• https://github.com/opennextjs/opennextjs-aws/pull/1199
• https://github.com/opennextjs/opennextjs-aws/pull/1200
• https://github.com/opennextjs/opennextjs-cloudflare/commit/38ea40b669be272ddf09a7df7e70c69d0b57404b
• https://github.com/opennextjs/opennextjs-cloudflare/releases/tag/@opennextjs/cloudflare@1.20.2
• https://github.com/advisories/GHSA-2vc4-c4r6-p6v6

Original description

OpenNext Cloudflare is an open Next.js adapter for Cloudflare. From 0.3.0 until 1.20.2, applications that enable enableCacheInterception, rely on middleware for access control, and have a matching cached protected route process encoded pathnames inconsistently between middleware matching and cache lookup. An unauthenticated attacker can use a percent-encoded pathname that does not match authorization middleware but decodes to the cache key of a protected route, causing cached content to be returned without authorization. Malformed encodings can also be partially decoded, allowing cache lookup to continue with a pathname that middleware did not evaluate consistently. This issue is fixed in version 1.20.2.