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.
Problem types
CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)
Product status
0.6.0 (semver) before 1.18.3
5bd90bb5cf0d15e375edc2a66fa322292940fce2 (git) before 340f75b5d191dc747ef7ac6365bd002d1cd55a9d
Credits
Peter Ullrich
Yordis Prieto
Jonatan Männchen
References
github.com/.../tesla/security/advisories/GHSA-mc85-72gr-vm9f
github.com/.../tesla/security/advisories/GHSA-mc85-72gr-vm9f
cna.erlef.org/cves/CVE-2026-48594.html
osv.dev/vulnerability/EEF-CVE-2026-48594
github.com/...ommit/340f75b5d191dc747ef7ac6365bd002d1cd55a9d