CVE-2021-32643

Description

### Impact `StaticFile.fromUrl` can leak the presence of a directory on a server when the `URL` scheme is not `file://`, and the URL points to a fetchable resource under its scheme and authority. The function returns `F[None]`, indicating no resource, if `url.getFile` is a directory, without first checking the scheme or authority of the URL. If a URL connection to the scheme and URL would return a stream, and the path in the URL exists as a directory on the server, the presence of the directory on the server could be inferred from the 404 response. The contents and other metadata about the directory are not exposed. This affects http4s versions: * 0.21.7 through 0.21.23 * 0.22.0-M1 through 0.22.0-M8 * 0.23.0-M1 * 1.0.0-M1 through 1.0.0-M22 ### Patches The [patch](https://github.com/http4s/http4s/commit/52e1890665410b4385e37b96bc49c5e3c708e4e9) is available in the following versions: * v0.21.24 * v0.22.0-RC1 * v0.23.0-RC1 * v1.0.0-M23 Note: a previous version of this advisory incorrectly referred to 0.22.0-M9 and 0.23.0-M2. ### Workarounds Don't call `StaticFile.fromUrl` with non-file URLs. ### For more information If you have any questions or comments about this advisory: * Open an issue in [the http4s repository](https://github.com/http4s/http4s) * Disclose further vulnerabilities according to the [http4s security policy](https://github.com/http4s/http4s/blob/main/SECURITY.md)

How to fix CVE-2021-32643

To remediate CVE-2021-32643, upgrade the affected package to a fixed version below.

• —upgrade to 0.21.24 or later

Is CVE-2021-32643 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• >= 0.21.7, < 0.21.24