High severity · published Sep 1, 2026
CVE-2026-69664
httpd parks a request worker indefinitely on a malformed chunk size sent after the headers
8.7
CVSS
0.9%
EPSS
No
On KEV
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 61% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OT
OTP · Erlang
18.1.4; 6.0.3; 77acb473d8f056f6f534395f131c6e45693797f0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-69664
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-69664
cna.erlef.org
https://cna.erlef.org/cves/CVE-2026-69664.html
github.com
https://github.com/erlang/otp/commit/77acb473d8f056f6f534395f131c6e45693797f0
github.com
https://github.com/erlang/otp/commit/a3adf63078438c86527d704e23282b7721d8ca12
github.com
https://github.com/erlang/otp/commit/bd4e74348c6be8a49f060da6fd48d43f3a960292
github.com
https://github.com/erlang/otp/commit/df1a9ca4666e2fdfc44886bfaae76de086d803f6
github.com
https://github.com/erlang/otp/security/advisories/GHSA-mr35-8h7w-w3gq
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