CVE-2021-39185

high-risk

Published 2021-09-01

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.

Do I need to act?

0.17% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 9.1/10 Critical

NETWORK / LOW complexity

Affected Products (20)

Http4S

Affected Vendors

Typelevel

References (4)

Third Party Advisory https://github.com/http4s/http4s/releases/tag/v0.23.2

Patch https://github.com/http4s/http4s/security/advisories/GHSA-52cf-226f-rhr6

Third Party Advisory https://github.com/http4s/http4s/releases/tag/v0.23.2

Patch https://github.com/http4s/http4s/security/advisories/GHSA-52cf-226f-rhr6

/ 100

high-risk

Severity 31/34 · Critical

Exploitability 1/34 · Minimal

Exposure 22/34 · High