CVE-2021-32643

StaticFile.fromUrl can leak presence of a directory

MEDIUM
5.8
CVSS Score
Published: May 27, 2021 at 05:15 PM UTC
Updated: June 17, 2026 at 03:53 AM UTC
2 products affected across 2 vendorsHTTP4SHTTP4S

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Severity
MEDIUM5.8
Exploit prediction
EPSS 1%

Description

Http4s is a Scala interface for HTTP services. `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, and 1.0.0-M1 through 1.0.0-M22. The [patch](https://github.com/http4s/http4s/commit/52e1890665410b4385e37b96bc49c5e3c708e4e9) is available in the following versions: v0.21.24, v0.22.0-M9, v0.23.0-M2, v1.0.0-M23. As a workaround users can avoid calling `StaticFile.fromUrl` with non-file URLs.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 0.22.0-M8v < 0.21.24v < 1.0.0-M23= 0.23.0-M1
Affected range stops below 0.21.24, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.0.0-M23, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

5.8MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-22

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