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.

Weaknesses 1

References 4

• cna.erlef.org https://cna.erlef.org/cves/CVE-2026-48594.html
• github.com https://github.com/elixir-tesla/tesla/commit/340f75b5d191dc747ef7ac6365bd002d1cd55a9d
• github.com https://github.com/elixir-tesla/tesla/security/advisories/GHSA-mc85-72gr-vm9f
• osv.dev https://osv.dev/vulnerability/EEF-CVE-2026-48594

Remediation