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MEDIUM severity

StaticFile.fromUrl can leak presence of a directoryGHSA-6h7w-fc84-x7p6

MEDIUMFix: http4s/http4s@52e1890

GHSA-6h7w-fc84-x7p6 is a medium-severity (CVSS 5.8) Path Traversal vulnerability in org.http4s:http4s-core. A fix is available for org.http4s:http4s-core — see the affected versions and patch details below.

Also known asCVE-2021-32643
Published
Updated
Affected
4 pkgs
Patched
4 / 4
Exploits
None indexed
Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs72th percentile — riskier than 72% of all scored CVEsHighest risk
0.00%0.63%1.26%1.90%0.3%1.4%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

GHSA-6h7w-fc84-x7p6 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

4 pkgs affected
☕org.http4s:http4s-core☕org.http4s:http4s-core☕org.http4s:http4s-core☕org.http4s:http4s-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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 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:

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.http4s:http4s-core≥ 0.21.7&&< 0.21.240.21.24org.http4s:http4s-core:0.21.24
☕Mavenorg.http4s:http4s-core≥ 0.22.0-M1&&< 0.22.0-RC10.22.0-RC1org.http4s:http4s-core:0.22.0-RC1
☕Mavenorg.http4s:http4s-core≥ 0.23.0-M1&&< 0.23.0-RC10.23.0-RC1org.http4s:http4s-core:0.23.0-RC1
☕Mavenorg.http4s:http4s-core≥ 1.0.0-M1&&< 1.0.0-M231.0.0-M23org.http4s:http4s-core:1.0.0-M23

Affected Products

1 product · 32 configurations
Application
http4stypelevel
≥ 0.21.7 && < 0.21.24
3 versions
0.22.00.23.01.0.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.http4s:http4s-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.http4s:http4s-core to 0.21.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6h7w-fc84-x7p6 is resolved across your whole dependency graph.

  3. Workarounds

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

### 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
O3 Security · Impact-Aware SCA

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StaticFile.fromUrl can leak presence of a directory