{"id":"CVE-2021-39185","details":"Http4s is a minimal, idiomatic Scala interface for HTTP services. In http4s versions 0.21.26 and prior, 0.22.0 through 0.22.2, 0.23.0, 0.23.1, and 1.0.0-M1 through 1.0.0-M24, the default CORS configuration is vulnerable to an origin reflection attack. The middleware is also susceptible to a Null Origin Attack. The problem is fixed in 0.21.27, 0.22.3, 0.23.2, and 1.0.0-M25. The original `CORS` implementation and `CORSConfig` are deprecated. See the GitHub GHSA for more information, including code examples and workarounds.","aliases":["GHSA-52cf-226f-rhr6"],"modified":"2026-05-16T04:03:06.328392146Z","published":"2021-09-01T20:15:07.447Z","database_specific":{},"references":[{"type":"ADVISORY","url":"https://github.com/http4s/http4s/releases/tag/v0.23.2"},{"type":"FIX","url":"https://github.com/http4s/http4s/security/advisories/GHSA-52cf-226f-rhr6"}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}