CVE-2026-32689

Source
https://cve.org/CVERecord?id=CVE-2026-32689
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-32689.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-32689
Aliases
Published
2026-05-05T15:17:30.664Z
Modified
2026-05-18T05:59:55.997591689Z
Severity
  • 8.7 (High) CVSS_V4 - 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 CVSS Calculator
Summary
Long-poll NDJSON body splitting causes unbounded memory allocation in Phoenix
Details

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.

Database specific
{
    "cwe_ids": [
        "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32689.json",
    "cna_assigner": "EEF",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "2674c6ea30634667f9b09966b90269393b445953"
                },
                {
                    "fixed": "*"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}
References

Affected packages

Git / github.com/phoenixframework/phoenix

Affected ranges

Type
GIT
Repo
https://github.com/phoenixframework/phoenix
Events

Affected versions

v1.*
v1.8.0
v1.8.1
v1.8.2
v1.8.3
v1.8.4
v1.8.5

Database specific

source
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-32689.json"