CVE-2026-70399
Received
Received - Intake
Denial of Service in Erlang/OTP Inets HTTP Server
Vulnerability report for CVE-2026-70399, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-01
Last updated on: 2026-09-01
Assigner: EEF
Description
Description
Allocation of Resources Without Limits or Throttling vulnerability in Erlang/OTP inets httpd allows an unauthenticated remote attacker to cause denial of service by opening and holding open a large number of connections. The max_clients option is documented to default to 150, and the inets hardening guide presents that limit as the first layer of denial-of-service defence, but a server that does not set it explicitly accepts an unlimited number of simultaneous connections. Establishing the connections is sufficient; no valid request and no authentication are required.
The accept gate in httpd_manager:handle_new_connection/4 reads the option with httpd_util:lookup/2, which returns undefined when the key is absent, rather than the three-argument form carrying the 150 default that the neighbouring get_ustate/2 uses. Erlang term ordering places every integer before every atom, so the Count =< Max guard holds for any connection count and the server never returns {reject, busy}. Each accepted connection occupies a worker process and a socket for as long as it is held, driving the node towards process, memory and file descriptor exhaustion. Servers that set max_clients explicitly are unaffected, because a configured value is applied as intended.
This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2.
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| erlang | otp | to 27.3.4.17 (exc) |
| erlang | otp | to 28.5.0.6 (exc) |
| erlang | otp | to 29.0.6 (exc) |
| erlang | inets | to 9.3.2.7 (exc) |
| erlang | inets | to 9.6.2.3 (exc) |
| erlang | inets | to 9.7.2 (exc) |
| erlang | otp | From 17.0 (exc) to 27.3.4.17 (exc) |
| erlang | otp | From 28.0 (exc) to 28.5.0.6 (exc) |
| erlang | otp | From 29.0 (exc) to 29.0.6 (exc) |
| erlang | inets | From 5.10 (exc) to 9.3.2.7 (exc) |
| erlang | inets | From 9.4 (exc) to 9.6.2.3 (exc) |
| erlang | inets | From 9.7 (exc) to 9.7.2 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-770 | The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. |
