Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing.
'Elixir.Plug.Conn':read_part_headers/2 in lib/plug/conn.ex does not obey its :length parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function read_part_body has an explicit byte_size(acc) > length guard that stops accumulation once a limit is reached. No such guard exists in read_part_headers. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service.
This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.
'Elixir.Plug.Conn':read_part_headers/2 in lib/plug/conn.ex does not obey its :length parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function read_part_body has an explicit byte_size(acc) > length guard that stops accumulation once a limit is reached. No such guard exists in read_part_headers. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service.
This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 14 May 2026 11:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. plug_multipart in src/plug_multipart.erl is a fork of the cow_multipart module from ninenines cowboy (CVE-2026-8466). The same unbounded accumulation pattern is present in 'Elixir.Plug.Conn':read_part_headers/2 in lib/plug/conn.ex: it accumulates incoming request bytes into a growing binary with no upper-bound check. When plug_multipart:parse_headers/2 returns more or {more, Buffer}, the function reads up to 64 KB from the underlying socket 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/8. 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 plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2. | Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. 'Elixir.Plug.Conn':read_part_headers/2 in lib/plug/conn.ex does not obey its :length parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function read_part_body has an explicit byte_size(acc) > length guard that stops accumulation once a limit is reached. No such guard exists in read_part_headers. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service. This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2. |
Thu, 14 May 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. plug_multipart in src/plug_multipart.erl is a fork of the cow_multipart module from ninenines cowboy (CVE-2026-8466). The same unbounded accumulation pattern is present in 'Elixir.Plug.Conn':read_part_headers/2 in lib/plug/conn.ex: it accumulates incoming request bytes into a growing binary with no upper-bound check. When plug_multipart:parse_headers/2 returns more or {more, Buffer}, the function reads up to 64 KB from the underlying socket 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/8. 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 plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2. | |
| Title | Unbounded buffer accumulation in multipart header parsing causes denial of service in plug | |
| First Time appeared |
Plug Project
Plug Project plug |
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| Weaknesses | CWE-770 | |
| CPEs | cpe:2.3:a:plug_project:plug:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Plug Project
Plug Project plug |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-05-14T10:56:21.031Z
Reserved: 2026-05-13T11:44:42.164Z
Link: CVE-2026-8468
No data.
Status : Received
Published: 2026-05-14T11:16:18.900
Modified: 2026-05-14T12:16:36.767
Link: CVE-2026-8468
No data.
OpenCVE Enrichment
Updated: 2026-05-14T12:30:19Z
Weaknesses