Erlang OTP prior 27.3.4.17/28.5.0.6/29.0.6 httpd httpd_request_handler:handle_info denial of service

Summaryinfo

A vulnerability classified as critical has been found in Erlang OTP. The affected element is the function httpd_request_handler:handle_info of the component httpd. This manipulation causes denial of service. This vulnerability is handled as CVE-2026-69664. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as critical was found in Erlang OTP. Affected by this vulnerability is the function httpd_request_handler:handle_info of the component httpd. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. The summary by CVE is:

Missing Release of Resource after Effective Lifetime vulnerability in Erlang/OTP inets httpd allows an unauthenticated remote attacker to cause denial of service by sending a request with a chunked body whose chunk-size line is not a hexadecimal number. The worker serving the connection is never released and no timeout reclaims it, so repeating the request across connections occupies every available worker and denies service to legitimate clients. No authentication is required and the default configuration is affected. The chunk-size line must arrive in a write separate from the headers. When the body accompanies the headers, httpd_request_handler:handle_body/3 calls http_chunk:decode/3 inside a try ... catch throw:Error, so the {error, {chunk_size, _}} thrown by http_chunk:decode_size/4 is answered with 400 Bad Request. When the chunk size arrives later, the decoder is resumed through a bare catch in httpd_request_handler:handle_info/2, which converts the throw into a return value rather than raising it; the resulting error tuple is then treated as the next decoder continuation, the socket is re-armed, and the worker waits for data that never comes. The request timeout has already been cancelled at the point the headers were accepted, and the periodic byte-rate check is only armed when minimum_bytes_per_second is configured, which it is not by default. This issue affects OTP from OTP 18.1.4 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 6.0.3 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-69664 since 08/17/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 27.3.4.17, 28.5.0.6 or 29.0.6 eliminates this vulnerability.

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Productinfo

Vendor

• Erlang

Name

• OTP

Website

• Product: https://github.com/erlang/otp/

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