CVE-2026-44582

Next.js is a React framework for building full-stack web applications. From 13.4.6 to before 15.5.16 and 16.2.5, React Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the _rsc cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL. This vulnerability is fixed in 15.5.16 and 16.2.5.

Next.js is a React framework for building full-stack web applications. From 13.4.6 to before 15.5.16 and 16.2.5, React Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the _rsc cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL. This vulnerability is fixed in 15.5.16 and 16.2.5.

### Impact React Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the `_rsc` cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL. ### Fix We strengthened the `_rsc` cache-busting mechanism to make practical collisions significantly harder and to better separate response variants that should not share cache entries. ### Workarounds If you cannot upgrade immediately, ensure intermediary caches correctly honor `Vary` for RSC-related request headers, or disable shared caching for affected RSC responses until you can deploy a patched release.

### Impact React Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the `_rsc` cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL. ### Fix We strengthened the `_rsc` cache-busting mechanism to make practical collisions significantly harder and to better separate response variants that should not share cache entries. ### Workarounds If you cannot upgrade immediately, ensure intermediary caches correctly honor `Vary` for RSC-related request headers, or disable shared caching for affected RSC responses until you can deploy a patched release.