Most recent entries from all

EUVD-2026-276722

fkie_cve-2026-32873

ewe is a Gleam web server. Versions 0.8.0 through 3.0.4 contain a bug in the handle_trailers function where rejected trailer headers (forbidden or undeclared) cause an infinite loop. When handle_trailers encounters such a trailer, three code paths (lines 520, 523, 526) recurse with the original buffer (rest) instead of advancing past the rejected header (Buffer(header_rest, 0)), causing decoder.decode_packet to re-parse the same header on every iteration. The resulting loop has no timeout or escape — the BEAM process permanently wedges at 100% CPU. Any application that calls ewe.read_body on chunked requests is affected, and this is exploitable by any unauthenticated remote client before control returns to application code, making an application-level workaround impossible. This issue is fixed in version 3.0.5.

GHSA-4w98-xf39-23gp — Loop with Unreachable Exit Condition ('Infinite Loop') in ewe

Affected: Hex: ewe

## Summary

ewe's `handle_trailers` function contains a bug where rejected trailer headers (forbidden or undeclared) cause an infinite loop. The function recurses with the original unparsed buffer instead of advancing past the rejected header, re-parsing the same header forever. Each malicious request permanently wedges a BEAM process at 100% CPU with no timeout or escape.

## Impact

When `handle_trailers` (`ewe/internal/http1.gleam:493`) encounters a trailer that is either not in the declared trailer set or is blocked by `is_forbidden_trailer`, three code paths (lines 520, 523, 526) recurse with the original buffer `rest` instead of `Buffer(header_rest, 0)`:

```gleam // Line 523 — uses `rest` (original buffer), not `Buffer(header_rest, 0)` (remaining) False -> handle_trailers(req, set, rest) ```

This causes `decoder.decode_packet` to re-parse the same header on every iteration, producing an infinite loop. The BEAM process never yields, never times out, and never terminates.

**Any ewe application that calls `ewe.read_body` on chunked requests is affected.** This is exploitable by any unauthenticated remote client. There is no application-level workaround — the infinite loop is triggered inside `read_body` before control returns to application code.

### Proof of Concept

**Send a chunked request with a forbidden trailer (`host`) to trigger the infinite loop:**

```sh printf 'POST / HTTP/1.1\r\nHost: localhost:8080\r\nTransfer-Encoding: chunked\r\nTrailer: host\r\n\r\n4\r…