Local file inclusion vulnerability in http4s

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.6 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

EPSS

• CVE-2020-5280: 6.98% estimated exploitation activity in the next 30 days; percentile 94.16 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact This vulnerability applies to all users of: org.http4s.server.staticcontent.FileService org.http4s.server.staticcontent.ResourceService org.http4s.server.staticcontent.WebjarService Path escaping URI normalization is applied incorrectly. Requests whose path info contain ../ or // can expose resources outside of the configured location. Specifically: FileService may expose any file on the local file system. ResourceService may expose any resource on the class path. Prefix matching When the service is configured with a non-empty pathPrefix that doesn't end in a slash, any directories whose names are a prefix of systemPath (from FileService) or pathPrefix (from ResourceService) are exposed. For example, if pathPrefix is /foo and systemPath is /bar, a request to /foobaz/quux.txt exposes file /barbaz/quux.txt, when only files beneath /bar should be available. URI decoding URI segments are not decoded before resource resolution. This causes resources with reserved characters in…

Published by the source

25 Mar 2020, 17:35 UTC

Last modified by the source

9 Jan 2023, 05:02 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-66q9-f7ff-mmx6

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# Patch Next advisory brief: CVE-2020-5280

Advisory: Local file inclusion vulnerability in http4s
IDs: CVE-2020-5280, GHSA-66q9-f7ff-mmx6
Record: https://patchnext.com/advisories/cve-2020-5280 (revision 1, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.http4s:http4s-server_2.12 0.21.2, 0.20.20, 0.18.26. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.http4s:http4s-server_2.12: affected < 0.18.26; >= 0.19.0, < 0.20.20; >= 0.21.0, < 0.21.2; fixed in 0.20.20, 0.21.2, 0.18.26

## Suggested inspection (read-only)
- Maven org.http4s:http4s-server_2.12: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.http4s:http4s-server_2.12.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-66q9-f7ff-mmx6 (GitHub-reviewed advisory GHSA-66q9-f7ff-mmx6 lists affected ranges: Maven org.http4s:http4s-server_2.12 >=0 =0.19.0 =0.21.0 <0.21.2)

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