CVE-2026-34715
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…
Does this matter?
Lower severity and a low EPSS score (0.33%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- EPSS
- 0.33% probability · 26th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-113
- Affected
- vshakitskiy/ewe
- Source
- security-advisories@github.com
References
- https://github.com/vshakitskiy/ewe/commit/ce4ff214d32626a10fda9398dc94a2d720e17446Patch
- https://github.com/vshakitskiy/ewe/releases/tag/v3.0.6Product, Release Notes
- https://github.com/vshakitskiy/ewe/security/advisories/GHSA-x2w3-23jr-hrpfExploit, Vendor Advisory
- https://github.com/vshakitskiy/ewe/security/advisories/GHSA-x2w3-23jr-hrpfExploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.