Vulnerability in Vshakitskiy Ewe
CVE-2026-34715
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (32.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 32.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Vshakitskiy Ewe — versions < 3.0.6
Weakness classification (CWE)
References
- github.com/vshakitskiy/ewe/security/advisories/GHSA-x2w3-23jr-hrpf (Exploit, Vendor Advisory)
- github.com/vshakitskiy/ewe/commit/ce4ff214d32626a10fda9398dc94a2d720e17446 (Patch)
- github.com/vshakitskiy/ewe/releases/tag/v3.0.6 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-34715?
- CVE-2026-34715 is a medium-severity vulnerability in Vshakitskiy Ewe, classified under HTTP Response Splitting. CVSS score: 5.3/10. Published 2026-04-02.
- How severe is CVE-2026-34715?
- Medium severity. CVSS v3 base score is 5.3 out of 10.