# CVE-2026-48594: Elixir Tesla denial of service via decompression bomb in compression middleware

Source: https://junglewise.ai/threats/cve-2026-48594-elixir-tesla-denial-of-service-via-decompression-bomb-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-02. Updated: 2026-07-10  
License: CC BY 4.0 with a link back

CVE-2026-48594 · Severity: high · CVSS 8.2 · Published 2026-06-02

Tesla is a popular HTTP client library for the Elixir programming language. A vulnerability exists where the library fails to limit the size of decompressed data when receiving responses from a server. An attacker-controlled server can send a specially crafted, highly compressed 'decompression bomb' that expands to gigabytes in memory, causing the application to crash or freeze and resulting in a denial of service.

## Quick answers

**Is CVE-2026-48594 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48594 being exploited in the wild.

**How severe is CVE-2026-48594?** High severity, with a CVSS score of 8.2, published 2 June 2026.

**Which products and versions are affected?** elixir-tesla tesla >= 0.6.0, < 1.18.3.

**Is there a fix for CVE-2026-48594?** A patch was published on 1.18.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-48594 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-48594?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the `Tesla.Middleware.DecompressResponse` and `Tesla.Middleware.Compression` components. The `decompress_body/2` function in `lib/tesla/middleware/compression.ex` recursively calls `:zlib.gunzip/1` or `:zlib.unzip/1` based on the `content-encoding` header without enforcing any output size limits. By providing multiple encoding tokens (e.g., 'gzip, gzip, gzip'), an attacker can achieve exponential data amplification. A small network payload can thus materialize as gigabytes of data on the BEAM heap, leading to memory exhaustion (CWE-409). The issue is fixed in version 1.18.3.

## Affected products

- elixir-tesla tesla >= 0.6.0, < 1.18.3

## Identifiers

- CVE-2026-48594
- GHSA-mc85-72gr-vm9f

## Timeline

- 2026-06-02: disclosed: Initial disclosure and NVD publication
- 2026-07-10: advisory: GitHub Advisory published/reviewed
- 1.18.3: patched

## References

- [https://api.github.com/users/PJUllrich](https://api.github.com/users/PJUllrich)
- [https://github.com/PJUllrich](https://github.com/PJUllrich)
- [https://api.github.com/users/PJUllrich/gists%7B/gist_id%7D](https://api.github.com/users/PJUllrich/gists%7B/gist_id%7D)
- [https://api.github.com/users/PJUllrich/repos](https://api.github.com/users/PJUllrich/repos)
- [https://avatars.githubusercontent.com/u/10426523?v=4](https://avatars.githubusercontent.com/u/10426523?v=4)
- [https://api.github.com/users/PJUllrich/events%7B/privacy%7D](https://api.github.com/users/PJUllrich/events%7B/privacy%7D)