CVE-2026-32689 (GCVE-0-2026-32689)

Vulnerability from cvelistv5 – Published: 2026-05-05 15:17 – Updated: 2026-05-05 15:41
VLAI?
Title
Long-poll NDJSON body splitting causes unbounded memory allocation in Phoenix
Summary
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.
Severity ?
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
EEF
References
Impacted products
Vendor Product Version
phoenixframework phoenix Affected: 1.7.0 , < 1.7.22 (semver)
Affected: 1.8.0 , < 1.8.6 (semver)
    cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*
 Create a notification for this product.
    phoenixframework phoenix Affected: 2674c6ea30634667f9b09966b90269393b445953 , < * (git)
    cpe:2.3:a:phoenixframework:phoenix:*:*:*:*:*:*:*:*
 Create a notification for this product.
Credits
Peter Ullrich
Show details on NVD website
To clipboard 

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          "collectionURL": "https://repo.hex.pm",
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              "value": "Allocation of Resources Without Limits or Throttling vulnerability in phoenixframework phoenix allows a denial of service via the long-poll transport\u0027s NDJSON body handling.\u003cp\u003eIn \u003ctt\u003e\u0027Elixir.Phoenix.Transports.LongPoll\u0027:publish/4\u003c/tt\u003e, when a POST request is received with \u003ctt\u003eContent-Type: application/x-ndjson\u003c/tt\u003e, the request body is split on newline characters using \u003ctt\u003eString.split/2\u003c/tt\u003e 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 \u2014 a 1 MB body produces approximately one million list elements, an 8 MB body approximately 8.4 million. Each element is then walked by \u003ctt\u003eEnum.map\u003c/tt\u003e, materializing another list of the same size. This exhausts BEAM memory and schedulers, crashing the node and terminating all active sessions.\u003c/p\u003e\u003cp\u003eA 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 \u003ctt\u003eOrigin\u003c/tt\u003e header, making this attack effectively unauthenticated.\u003c/p\u003e\u003cp\u003eThis issue affects phoenix: from 1.7.0 before 1.7.22 and 1.8.6.\u003c/p\u003e"
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Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.