EEF-CVE-2026-8468

Unbounded buffer accumulation in multipart header parsing causes denial of service in plug

## Summary 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. ## Configurations The application must use Plug.Parsers with the :multipart parser, or otherwise call Plug.Conn.read\_part\_headers/2 to process multipart/form-data request bodies. Deployments that do not handle multipart uploads are not affected.