Authorization header leaks to third-party origin on cross-origin redirect in Tesla.Middleware.FollowRedirects
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.
- Published
- Jun 2, 2026
- Updated
- Sep 24, 2026
- EPSS
- 0.7% · 50th percentile
- CWE
- CWE-178
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Report tools
Action score
32
Monitor
Low priority for now.
- CVSS
- 32 / 40 · 8.2 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.7%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · EEF
- 8.2
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| elixir-tesla | tesla | cpe:2.3:a:elixir-tesla:tesla |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- elixir-tesla tesla1.4.0 and later · before 1.18.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.
elixir-tesla tesla
- 1.4.0 and later · before 1.18.3affected · semver
- 2d937d5813d7cda5cd726f41824985fb655c920f and later · before db963dba67651b9abd1fc420a1d9679cf6efe182affected · git
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Hex | tesla | from 0.6.0 · before 1.18.3 | 1.18.3 |
| Hex | tesla | from 1.4.0 · before 1.18.3 | 1.18.3 |
Same product
elixir-tesla: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-48597Atom table exhaustion via untrusted URL scheme in Tesla.Adapter.Mint32Monitor
- CVE-2026-48594Decompression bomb in Tesla.Middleware.DecompressResponse and Tesla.Middleware.Compression32Monitor
- CVE-2026-48598CRLF injection in Tesla.Multipart disposition parameters allows multipart part header injection8Monitor
- CVE-2026-48596CRLF injection in Tesla.Multipart.add_content_type_param/2 allows HTTP header injection8Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| elixir-tesla tesla | 1.18.3 | Vendor (CNA) |
| elixir-tesla tesla | db963dba67651b9abd1fc420a1d9679cf6efe182 | Vendor (CNA) |
| Hex:tesla | 1.18.3 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Peter Ullrichfinder
- Yordis Prietoremediation developer
- Jonatan Männchen / EEFanalyst
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-178 · Improper Handling of Case SensitivityCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- cna.erlef.org/cves/CVE-2026-48595.html
- github.com/elixir-tesla/tesla/commit/2d937d5813d7cda5cd726f41824985fb655c920f
- github.com/elixir-tesla/tesla/commit/db963dba67651b9abd1fc420a1d9679cf6efe182
- osv.dev/vulnerability/EEF-CVE-2026-48595
Vendor advisories and official records. Exploit/PoC links are deliberately left out.