CVE-2026-69664

httpd parks a request worker indefinitely on a malformed chunk size sent after the headers

HIGH
8.7
CVSS Score
Published: September 1, 2026 at 02:59 PM UTC
Updated: September 22, 2026 at 10:17 AM UTC
1 product affected across 1 vendorErlang /otp

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Severity
HIGH8.7
Exploit prediction
EPSS 0.9%
SSVC
PoC

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, 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≥ 18.1.4v ≥ 6.0.318.1.4 ≤ v < 27.3.4.1728.0 ≤ v < 28.5.0.629.0 ≤ v < 29.0.618.1.46.0.377acb473d8f056f6f534395f131c6e45693797f0
Affected range stops below 27.3.4.17, so it looks safe — our inference, not a vendor statement
Affected range stops below 28.5.0.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 29.0.6, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.7HIGHEEF
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-772

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