Http4S
CVE-2021-32643
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Path canonicalization, traversal prevention
MITRE ATT&CK
2 techniques across 2 tactics: Discovery, Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 5.8 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could access files and directories outside the intended path by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
Get an e-mail when this CVE is exploited, patched or re-scored. Free account.
Alert meAnalysisAI
Http4s is a Scala interface for HTTP services. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Path Traversal vulnerability could allow attackers to access files and directories outside the intended path.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Validate and canonicalize file paths. Use chroot or sandboxing. Reject input containing path separators or '../' sequences.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in maven
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Path Traversal (CWE-22), which allows attackers to access files and directories outside the intended path. 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 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 products include: Typelevel Http4S. Version information: through 0.21.23.
Know when Http4S gets its next vulnerability
- Watch products and get an email when something new is published
- Check this CVE against your own stack and servers
- Exploit and PoC references, threat intelligence from 22 sources
No credit card · 7-day full trial
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
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 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.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.
Affected Products (CPE)NVD
XML External Entity (XXE) injection in http4s-scala-xml's EntityDecoder for scala.xml.Elem (all versions before 0.24.1 a
Http4s client applications that keep a cookie jar can leak stored cookies — including session and authentication cookies
Http4s is a Scala interface for HTTP services. Rated medium severity (CVSS 6.3), this vulnerability is remotely exploita
Http4s is a Scala interface for HTTP services. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploita
Request smuggling in the http4s Ember HTTP/1.1 parser lets an unauthenticated, remote attacker bypass front-end access c
Http4s is a minimal, idiomatic Scala interface for HTTP services. Rated critical severity (CVSS 9.1), this vulnerability
HTTP request smuggling in http4s Ember (all releases prior to 0.23.35 and 1.0.0-M47) lets an unauthenticated remote atta
Let me synthesize. CVE-2026-69205: http4s Ember HTTP parser request smuggling via Transfer-Encoding header case-sensiti
http4s is an open source scala interface for HTTP. Rated medium severity (CVSS 4.7), this vulnerability is remotely expl
A crafted WebSocket frame can pin a worker thread and exhaust memory in the http4s Scala HTTP library, causing denial of
Heap exhaustion in the http4s Ember backend (0.23.x before 0.23.35 and 1.0.0 milestones before 1.0.0-M47) allows a singl
Heap-exhaustion denial of service in the http4s DigestAuth server middleware: an inverted stale-nonce comparison in Nonc
Exploit-DB