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CVE-2026-69212

Http4s: FollowRedirect middleware leaks credentials over https->http same-authority redirect

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.23.35, 1.0.0-M47
1 proof of concept on GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The FollowRedirect client middleware strips Authorization and Cookie headers only when a redirect changes authority, but authority comparison excludes the URI scheme. A same-authority redirect from HTTPS to HTTP therefore preserves credentials and transmits them over a plaintext connection. An attacker who can induce the downgrade and observe the network can capture those sensitive headers from applications using FollowRedirect. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • http4s http4s

    fixed in 0.23.35; From 1.0.0-M1 · fixed in 1.0.0-M47

References 5

GitHub · http4s/http4s

GitHub · c0gnit00/CVE-2026-69212