CVE-2026-69664: CWE-772 Missing Release of Resource after Effective Lifetime in Erlang OTP
Description
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, OTP 28.5.0.6, and OTP 29.0.6, corresponding to inets from 6.0.3 before 9.3.2.7, 9.6.2.3, and 9.7.2.
CVSS v4.0
Score 8.7high
Affected software
Erlang
OTP
Erlang
OTP
Erlang
OTP
cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-69664) in Erlang/OTP's inets httpd module involves a missing release of a worker resource after receiving a malformed chunked HTTP request body. Specifically, when the chunk-size line is invalid and arrives separately from the headers, the error handling path causes the worker to wait indefinitely for data that never arrives. The request timeout is cancelled upon header acceptance, and the byte-rate check is disabled by default, so the worker is never reclaimed. This leads to exhaustion of all available workers, resulting in denial of service. The issue affects OTP versions from 18.1.4 up to but excluding 27.3.4.17, and inets versions from 6.0.3 up to but excluding 9.3.2.7, as well as certain later versions noted.
Potential Impact
An unauthenticated remote attacker can cause a denial of service by exhausting all available worker processes in the inets httpd server. This prevents legitimate clients from being served, effectively disrupting service availability. No authentication or special privileges are required, and the default configuration is vulnerable.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is applied, consider configuring minimum_bytes_per_second to enable the periodic byte-rate check, which can help reclaim stuck workers. Monitor for unusual connection patterns that may indicate exploitation attempts.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- EEF
- Date Reserved
- 2026-08-17T10:45:02.808Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a96edc2acd9273b49deccd0
Added to database: 09/01/2026, 15:22:42 UTC
Last enriched: 09/23/2026, 02:28:24 UTC
Last updated: 10/15/2026, 18:48:22 UTC
Views: 73
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