Description
ewe is a Gleam web server. Prior to version 3.0.6, the encode_headers function in src/ewe/internal/encoder.gleam directly interpolates response header keys and values into raw HTTP bytes without validating or stripping CRLF (\r\n) sequences. An application that passes user-controlled data into response headers (e.g., setting a Location redirect header from a request parameter) allows an attacker to inject arbitrary HTTP response content, leading to response splitting, cache poisoning, and possible cross-site scripting. Notably, ewe does validate CRLF in incoming request headers via validate_field_value() in the HTTP/1.1 parser — but provides no equivalent protection for outgoing response headers in the encoder. This issue has been patched in version 3.0.6.
Affected products
vshakitskiy: ewe
References4
- github.com/vshakitskiy/ewe/security/advisories/GHSA-x2w3-23jr-h… ExploitVendor Advisory
- github.com/vshakitskiy/ewe/security/advisories/GHSA-x2w3-23jr-h… ExploitVendor Advisory
- github.com/vshakitskiy/ewe/commit/ce4ff214d32626a10fda9398dc94a… Patch
- github.com/vshakitskiy/ewe/releases/tag/v3.0.6 ProductRelease Notes
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 28 · as of 12 November 2026
- CWE
- CWE-113
Could this be exploited in your environment?
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