CVE-2026-32689— Long-poll NDJSON body splitting causes unbounded memory allocation in Phoenix

Long-poll NDJSON body splitting causes unbounded memory allocation in Phoenix

Allocation of Resources Without Limits or Throttling vulnerability in phoenixframework phoenix allows a denial of service via the long-poll transport's NDJSON body handling. In 'Elixir.Phoenix.Transports.LongPoll':publish/4, when a POST request is received with Content-Type: application/x-ndjson, the request body is split on newline characters using String.split/2 with no limit on the number of resulting segments. An attacker can send a body consisting entirely of newline bytes, causing a 1:1 amplification into a list of empty binaries — a 1 MB body produces approximately one million list elements, an 8 MB body approximately 8.4 million. Each element is then walked by Enum.map, materializing another list of the same size. This exhausts BEAM memory and schedulers, crashing the node and terminating all active sessions. A session token required to reach the vulnerable endpoint is freely obtainable by any client via an unauthenticated GET request to the same URL with a matching Origin header, making this attack effectively unauthenticated. This issue affects phoenix: from 1.7.0 before 1.7.22 and 1.8.6.

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不加限制或调节的资源分配

phoenix 安全漏洞

phoenix是Phoenix framework开源的一款Web开发框架。 phoenix 1.7.0至1.7.22之前版本和1.8.6版本存在安全漏洞，该漏洞源于长轮询传输的NDJSON主体处理中资源分配无限制，可能导致拒绝服务攻击。

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