Http4s: ResourceService and Webjar Service path escape via percent-encoded separators
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-22 and the CVSS impact.
Summary
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, ResourceService and WebjarService decode each URL path segment but reject only segments exactly equal to an empty string, a dot, or two dots. A request containing percent-encoded slash or backslash separators can turn an accepted segment into a parent-directory traversal after decoding, allowing access to classpath or WebJar resources outside the configured base when a directory-backed classpath is served and the backend preserves the encoded separator. The patch rejects decoded segments containing slash or backslash in ResourceService and WebjarService, and applies the same guard to the non-exploitable FileService for consistency. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| http4s | http4s | before 0.23.35; 1.0.0-M1 to before 1.0.0-M47 | 0.23.35, 1.0.0-M47 | Patch available | CNA |
| — | org.http4s:http4s-server_2.12 (Maven) | before 0.23.35 | 0.23.35 | Patch available | GHSA-crq5-92j2-j7wv |
| — | org.http4s:http4s-server_2.13 (Maven) | before 0.23.35 | 0.23.35 | Patch available | GHSA-crq5-92j2-j7wv |
| — | org.http4s:http4s-server_3 (Maven) | before 0.23.35 | 0.23.35 | Patch available | GHSA-crq5-92j2-j7wv |
| — | org.http4s:http4s-server_3 (Maven) | 1.0.0-M1 to before 1.0.0-M47 | 1.0.0-M47 | Patch available | GHSA-crq5-92j2-j7wv |
| — | org.http4s:http4s-server_2.13 (Maven) | 1.0.0-M1 to before 1.0.0-M47 | 1.0.0-M47 | Patch available | GHSA-crq5-92j2-j7wv |
- http4s Vendorhttp4s Affected before 0.23.35; 1.0.0-M1 to before 1.0.0-M47 Fixed in 0.23.35, 1.0.0-M47 Patch available CNA
- org.http4s:http4s-server_2.12 (Maven) Vendor— Affected before 0.23.35 Fixed in 0.23.35 Patch available GHSA-crq5-92j2-j7wv
- org.http4s:http4s-server_2.13 (Maven) Vendor— Affected before 0.23.35 Fixed in 0.23.35 Patch available GHSA-crq5-92j2-j7wv
- org.http4s:http4s-server_3 (Maven) Vendor— Affected before 0.23.35 Fixed in 0.23.35 Patch available GHSA-crq5-92j2-j7wv
- org.http4s:http4s-server_3 (Maven) Vendor— Affected 1.0.0-M1 to before 1.0.0-M47 Fixed in 1.0.0-M47 Patch available GHSA-crq5-92j2-j7wv
- org.http4s:http4s-server_2.13 (Maven) Vendor— Affected 1.0.0-M1 to before 1.0.0-M47 Fixed in 1.0.0-M47 Patch available GHSA-crq5-92j2-j7wv
Remediation
- Fix · CNA http4s (http4s) Fixed in 0.23.35, 1.0.0-M47
- Fix · GHSA-crq5-92j2-j7wv org.http4s:http4s-server_2.12 (Maven) Fixed in 0.23.35 Advisory →
- Fix · GHSA-crq5-92j2-j7wv org.http4s:http4s-server_2.13 (Maven) Fixed in 0.23.35 Advisory →
- Fix · GHSA-crq5-92j2-j7wv org.http4s:http4s-server_3 (Maven) Fixed in 0.23.35 Advisory →
- Fix · GHSA-crq5-92j2-j7wv org.http4s:http4s-server_3 (Maven) Fixed in 1.0.0-M47 Advisory →
- Fix · GHSA-crq5-92j2-j7wv org.http4s:http4s-server_2.13 (Maven) Fixed in 1.0.0-M47 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-69201
- 2026-10-03 Alias added: GHSA-crq5-92j2-j7wv
References
Other 5
More http4s vulnerabilities
- TI-2022-13223 mTLS client verification is skipped in fs2 on Node.js CVSS 3.1CRITICAL 9.8
- TI-2023-08714 Http4s has fatal error parsing User-Agent and Server headers CVSS 3.1HIGH 7.5
- TI-2022-06031 Hash collision in typelevel jawn CVSS 3.1HIGH 7.5
- TI-2025-37261 Http4s vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section CVSS 4.0MEDIUM 6.3
- TI-2026-44185 http4s-scala-xml has an XML External Entity (XXE) processing issue CVSS 3.1CRITICAL 9.3
- TI-2020-04336 Local file inclusion vulnerability in http4s CVSS 3.1HIGH 7.6
Sources
- CVE-2026-69201 · CVE Program
- CVE-2026-69201 · NVD
- FIRST EPSS
- GHSA-crq5-92j2-j7wv · GitHub Advisory Database · CC BY 4.0
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