CVE-2026-48594
Fix: elixir-tesla/tesla@340f75bCVE-2026-48594 is a CWE-409 vulnerability in tesla. O3 Security confirms whether CVE-2026-48594 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Decompression bomb in Tesla.Middleware.DecompressResponse and Tesla.Middleware.Compression
Real-World Exposure
teslaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in elixir-tesla tesla allows a denial of service via decompression bomb in HTTP response bodies.
When Tesla.Middleware.DecompressResponse or Tesla.Middleware.Compression is included in a Tesla middleware pipeline, HTTP response bodies are decompressed eagerly with no size limit. The decompress_body/2 function in lib/tesla/middleware/compression.ex passes the entire response body to :zlib.gunzip/1 or :zlib.unzip/1 without any cap on the output size. Additionally, compression_algorithms/1 splits the content-encoding header on commas and decompress_body/2 recurses once per token, applying a decompression pass on each iteration. A server advertising content-encoding: gzip, gzip, gzip, gzip causes four recursive decompression passes, yielding exponential amplification: each gzip layer can expand its input roughly 1000x, so a payload of a few hundred bytes on the wire inflates to gigabytes of BEAM heap, exhausting memory and crashing or freezing the calling process.
This issue affects tesla: from 0.6.0 before 1.18.3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | tesla | ≥ 0.6.0&&< 1.18.3 | 1.18.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tesla. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update tesla to 1.18.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-48594 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-48594 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-48594. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-48594 in your dependencies?
O3 detects CVE-2026-48594 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.