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Medium · 5.9 Public exploit CVE-2026-69212 EUVD-2026-79186

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

Published Sep 15, 2026 · Updated Sep 15, 2026 · Assigned by GitHub_M

Vendor: http4s Product: http4s

Description

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.

Affected products

VendorProductAffectedFixed
http4s http4s < 0.23.35, >= 1.0.0-M1, < 1.0.0-M47 —

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 1 repository

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

References