CVE-2026-48595 Authorization header leaks to third-party origin on cross-origin redirect in Tesla.Middleware.FollowRedirects
Attackers can steal Authorization headers via cross-origin redirects due to case-sensitive header filtering in Tesla.Middleware.FollowRedirects.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48595?
CVE-2026-48595 is a high-severity vulnerability in elixir-tesla tesla, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-178
Which versions are affected by CVE-2026-48595?
3 open source packages ship an affected version, including tesla. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
tesla Hex | From 0.6.0 | 1.18.3 |
tesla Hex | From 0.6.0 | 1.18.3 |
tesla Hex | From 1.4.0 | 1.18.3 |
Products include Elixir-Tesla Tesla.
How do I fix CVE-2026-48595?
Upgrade tesla to 1.18.3 or later.
Is CVE-2026-48595 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48595 exists.
Other vulnerabilities in elixir-tesla tesla
- CVE-2026-48594 Decompression bomb in Tesla.Middleware.DecompressResponse and Tesla.Middleware.Compression
- CVE-2026-48597 Atom table exhaustion via untrusted URL scheme in Tesla.Adapter.Mint
- CVE-2026-48596 CRLF injection in Tesla.Multipart.add_content_type_param/2 allows HTTP header injection
- CVE-2026-48598 CRLF injection in Tesla.Multipart disposition parameters allows multipart part header injection
Sources
Also known as EEF-CVE-2026-48595, GHSA-9m9w-gxf7-rh8m.