Tesla.Middleware.FollowRedirects strips security-sensitive headers on cross-origin redirects using a case-sensitive string comparison against a lowercase filter list (@filter_headers ["authorization", "host"]). HTTP header names are case-insensitive per RFC 7230, but Tesla preserves header keys verbatim as supplied by the caller without normalizing case. A header set as {"Authorization", "Bearer …"} (the RFC 7235 canonical casing used by virtually all HTTP libraries and documentation) does not match the lowercase filter entry and is forwarded to the redirect destination. An attacker who can control or influence a Location: response seen by the client (via their own endpoint, a redirect-open upstream, or a compromised origin) receives the bearer token or other Authorization material on the cross-origin request.
This issue affects tesla: from 1.4.0 before 1.18.3.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
Normalize all header keys to lowercase before passing them to Tesla. Use "authorization" instead of "Authorization" when setting headers via Tesla.put_header/3 or Tesla.Middleware.Headers.
Wed, 03 Jun 2026 02:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Improper Handling of Case Sensitivity vulnerability in elixir-tesla tesla allows credential leakage to a third-party origin on cross-origin redirects. Tesla.Middleware.FollowRedirects strips security-sensitive headers on cross-origin redirects using a case-sensitive string comparison against a lowercase filter list (@filter_headers ["authorization", "host"]). HTTP header names are case-insensitive per RFC 7230, but Tesla preserves header keys verbatim as supplied by the caller without normalizing case. A header set as {"Authorization", "Bearer …"} (the RFC 7235 canonical casing used by virtually all HTTP libraries and documentation) does not match the lowercase filter entry and is forwarded to the redirect destination. An attacker who can control or influence a Location: response seen by the client (via their own endpoint, a redirect-open upstream, or a compromised origin) receives the bearer token or other Authorization material on the cross-origin request. This issue affects tesla: from 1.4.0 before 1.18.3. | |
| Title | Authorization header leaks to third-party origin on cross-origin redirect in Tesla.Middleware.FollowRedirects | |
| First Time appeared |
Elixir-tesla
Elixir-tesla tesla |
|
| Weaknesses | CWE-178 | |
| CPEs | cpe:2.3:a:elixir-tesla:tesla:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Elixir-tesla
Elixir-tesla tesla |
|
| References |
| |
| Metrics |
cvssV4_0
|
Projects
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-06-02T19:12:24.989Z
Reserved: 2026-05-22T09:36:56.834Z
Link: CVE-2026-48595
No data.
Status : Received
Published: 2026-06-02T20:16:38.390
Modified: 2026-06-02T20:16:38.390
Link: CVE-2026-48595
No data.
OpenCVE Enrichment
Updated: 2026-06-03T04:30:05Z