Vulnerability Description
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.
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-32689.html
- https://github.com/phoenixframework/phoenix/commit/1a67c61ff9ce0a7711662ac735486
- https://github.com/phoenixframework/phoenix/commit/912ea181fd247c21dbcc49fb97d00
- https://github.com/phoenixframework/phoenix/security/advisories/GHSA-628h-q48j-j
- https://osv.dev/vulnerability/EEF-CVE-2026-32689
FAQ
What is CVE-2026-32689?
CVE-2026-32689 is a documented vulnerability. 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.Transp...
How severe is CVE-2026-32689?
CVSS scoring is not yet available for CVE-2026-32689. Check NVD for updates.
Is there a patch for CVE-2026-32689?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.