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2 vulnerabilities found for cowboy by ninenines

CVE-2026-65624 (GCVE-0-2026-65624)
Vulnerability from cvelistv5
Published
2026-07-28 10:01
Modified
2026-07-29 04:17
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Summary
Allocation of Resources Without Limits or Throttling vulnerability in ninenines cowboy allows an unauthenticated remote attacker to exhaust connection process memory over HTTP/1.1. The HTTP/1.1 handler in cowboy_http enforces the max_headers limit by counting the number of distinct header names in a map (maps:size(Headers)). When a request contains multiple header lines with the same name, the values are concatenated into a single ever-growing binary stored under that one map key (", " for regular headers, "; " for cookies), so the map size stays at one and the max_headers cap (default 100) is never reached. Because no accumulator bounds the total number of header lines or the total byte size of the header block (only per-line max_header_name_length and max_header_value_length apply), an unauthenticated client can send an arbitrary number of header lines with the same name and grow the connection process's binary memory to arbitrary size within the request window. The impact per connection is bounded by request_timeout (default 5 seconds, not reset by header data), and by max_heap_size when set (the offending connection process is killed once its heap grows past the limit). When max_heap_size is left at the default (unset), sustained abuse can drive the Erlang VM into out-of-memory conditions. This issue affects cowboy from 2.0.0-pre.4 before 2.18.0.
Impacted products
Vendor Product Version
ninenines cowboy Version: 2.0.0-pre.4   
    cpe:2.3:a:ninenines:cowboy:*:*:*:*:*:*:*:*
Create a notification for this product.
   ninenines cowboy Version: 309780a9fda145c262a47ac7811ffd50a0271c5b
    cpe:2.3:a:ninenines:cowboy:*:*:*:*:*:*:*:*
Create a notification for this product.
Show details on NVD website


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CVE-2026-8466 (GCVE-0-2026-8466)
Vulnerability from cvelistv5
Published
2026-05-13 18:26
Modified
2026-05-14 04:30
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Summary
Allocation of Resources Without Limits or Throttling vulnerability in ninenines cowboy allows denial of service via unbounded buffer accumulation in multipart header parsing. cowboy_req:read_part/3 in src/cowboy_req.erl accumulates incoming request bytes into a Buffer binary with no upper-bound check. When cow_multipart:parse_headers/2 returns more or {more, Buffer2}, the function reads up to Length bytes (default 64 KB) from the request body and recurses with the enlarged buffer. There is no equivalent of the byte_size(Acc) > Length guard present in the sibling function read_part_body/4. An unauthenticated attacker can send a multipart/form-data request whose body never yields a complete header section — for example, a body that never contains the advertised boundary delimiter, or one whose header lines never contain \r\n\r\n — and force the server process to accumulate memory linearly with the bytes the protocol layer is willing to deliver. A handful of concurrent such uploads is sufficient to exhaust BEAM memory. This issue affects cowboy from 2.0.0 before 2.15.0.
Impacted products
Vendor Product Version
ninenines cowboy Version: 2.0.0   
    cpe:2.3:a:ninenines:cowboy:*:*:*:*:*:*:*:*
Create a notification for this product.
   ninenines cowboy Version: 917cf99e10c41676183d501b86af6e47c95afb89
    cpe:2.3:a:ninenines:cowboy:*:*:*:*:*:*:*:*
Create a notification for this product.
Show details on NVD website


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