# CVE-2021-32643: StaticFile.fromUrl can leak presence of a directory > Attackers can infer the existence of server directories via StaticFile.fromUrl, leaking internal filesystem structure information. - **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 27 May 2021 - **Updated:** 3 Aug 2024 - **Also known as:** GHSA-6h7w-fc84-x7p6 ## What is CVE-2021-32643? CVE-2021-32643 is a medium-severity vulnerability in http4s, published on 27 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Which versions are affected by CVE-2021-32643? 8 open source packages ship an affected version, including org.http4s:http4s-core. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.http4s:http4s-core` | Maven | From 0.21.7 | 0.21.24 | | `org.http4s:http4s-core` | Maven | From 0.21.7 | 0.21.24 | | `org.http4s:http4s-core` | Maven | From 0.22.0-M1 | 0.22.0-RC1 | | `org.http4s:http4s-core` | Maven | From 0.22.0-M1 | 0.22.0-RC1 | | `org.http4s:http4s-core` | Maven | From 0.23.0-M1 | 0.23.0-RC1 | | `org.http4s:http4s-core` | Maven | From 0.23.0-M1 | 0.23.0-RC1 | | `org.http4s:http4s-core` | Maven | From 1.0.0-M1 | 1.0.0-M23 | | `org.http4s:http4s-core` | Maven | From 1.0.0-M1 | 1.0.0-M23 | Products: Typelevel Http4s. ## How do I fix CVE-2021-32643? Upgrade org.http4s:http4s-core to a fixed version for your release line: 0.21.24, 0.22.0-RC1, 0.23.0-RC1 or 1.0.0-M23. ## Is CVE-2021-32643 being exploited? There is no known exploitation of CVE-2021-32643 in the wild and no public exploit code. ## Other vulnerabilities in http4s - [CVE-2021-39185](https://insights.sbomify.com/CVE-2021-39185/): Default CORS config allows any origin with credentials (critical 9.1) - [CVE-2021-41084](https://insights.sbomify.com/CVE-2021-41084/): Response Splitting from unsanitized headers in http4s (high 8.7) - [CVE-2020-5280](https://insights.sbomify.com/CVE-2020-5280/): Local file inclusion vulnerability in http4s (high 7.6) - [CVE-2023-22465](https://insights.sbomify.com/CVE-2023-22465/): Http4s has fatal error parsing User-Agent and Server headers (high 7.5) - [CVE-2021-21294](https://insights.sbomify.com/CVE-2021-21294/): Unbounded connection acceptance in http4s-blaze-server (high 7.5) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-32643 and fix it if it is affected. What it is: CVE-2021-32643 is a medium-severity vulnerability in http4s, published on 27 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2021-32643 in the wild and no public exploit code. Affected packages and fixed versions: - org.http4s:http4s-core (Maven): affected from 0.21.7; fixed in 0.21.24 - org.http4s:http4s-core (Maven): affected from 0.21.7; fixed in 0.21.24 - org.http4s:http4s-core (Maven): affected from 0.22.0-M1; fixed in 0.22.0-RC1 - org.http4s:http4s-core (Maven): affected from 0.22.0-M1; fixed in 0.22.0-RC1 - org.http4s:http4s-core (Maven): affected from 0.23.0-M1; fixed in 0.23.0-RC1 - org.http4s:http4s-core (Maven): affected from 0.23.0-M1; fixed in 0.23.0-RC1 - org.http4s:http4s-core (Maven): affected from 1.0.0-M1; fixed in 1.0.0-M23 - org.http4s:http4s-core (Maven): affected from 1.0.0-M1; fixed in 1.0.0-M23 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2021-32643/ (Markdown: https://insights.sbomify.com/CVE-2021-32643/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32643 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32643 - OSV: https://osv.dev/vulnerability/CVE-2021-32643 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-32643/ Summaries are generated and may contain mistakes; the official description above is the record.