# CVE-2026-48596: CRLF injection in Tesla.Multipart.add_content_type_param/2 allows HTTP header injection

> Attackers can inject arbitrary HTTP headers into outbound requests via unvalidated CRLF sequences in multipart content type parameters.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Jun 2026
- **Updated:** 24 Sep 2026
- **Also known as:** EEF-CVE-2026-48596, GHSA-q7jx-v53g-848w

## What is CVE-2026-48596?

CVE-2026-48596 is a low-severity vulnerability in elixir-tesla tesla, published on 2 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in elixir-tesla tesla allows HTTP header injection via Tesla.Multipart.add_content_type_param/2.

Tesla.Multipart.add_content_type_param/2 appends caller-supplied strings to the multipart content_type_params list without validating for CR (\r) or LF (\n) characters. Tesla.Multipart.headers/1 then joins these params verbatim with "; " to construct the outgoing Content-Type header value. A param containing \r\n splits the header line, allowing arbitrary headers to be injected into the outbound HTTP request. Any application that forwards untrusted input (such as a user-supplied charset or parameter string) into add_content_type_param/2 is affected.

This issue affects tesla: from 0.8.0 before 1.18.3.

Weakness: CWE-113 (Improper Neutralization of CRLF Sequences in HTTP Headers)

## Which versions are affected by CVE-2026-48596?

3 open source packages ship an affected version, including tesla. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tesla` | Hex | From 0.8.0 | 1.18.3 |
| `tesla` | Hex | From 0.8.0 | 1.18.3 |
| `tesla` | Hex | From 0.8.0 | 1.18.3 |

Products: Elixir-Tesla Tesla.

## How do I fix CVE-2026-48596?

Upgrade tesla to 1.18.3 or later.

## Is CVE-2026-48596 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48596 exists.

## Other vulnerabilities in elixir-tesla tesla

- [CVE-2026-48594](https://insights.sbomify.com/CVE-2026-48594/): Decompression bomb in Tesla.Middleware.DecompressResponse and Tesla.Middleware.Compression (high 8.2)
- [CVE-2026-48595](https://insights.sbomify.com/CVE-2026-48595/): Authorization header leaks to third-party origin on cross-origin redirect in Tesla.Middleware.FollowRedirects (high 8.2)
- [CVE-2026-48597](https://insights.sbomify.com/CVE-2026-48597/): Atom table exhaustion via untrusted URL scheme in Tesla.Adapter.Mint (high 8.2)
- [CVE-2026-48598](https://insights.sbomify.com/CVE-2026-48598/): CRLF injection in Tesla.Multipart disposition parameters allows multipart part header injection (low 2.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48596 and fix it if it is affected.

What it is: CVE-2026-48596 is a low-severity vulnerability in elixir-tesla tesla, published on 2 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48596 exists.

Affected packages and fixed versions:
- tesla (Hex): affected from 0.8.0; fixed in 1.18.3
- tesla (Hex): affected from 0.8.0; fixed in 1.18.3
- tesla (Hex): affected from 0.8.0; fixed in 1.18.3

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48596/ (Markdown: https://insights.sbomify.com/CVE-2026-48596/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48596
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48596
- OSV: https://osv.dev/vulnerability/CVE-2026-48596

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48596/
Summaries are generated and may contain mistakes; the official description above is the record.