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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.

PUBLISHED Reserved 2026-05-22 | Published 2026-06-02 | Updated 2026-06-04 | Assigner EEF




HIGH: 8.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Problem types

CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

Product status

Default status
unaffected

0.6.0 (semver) before 1.18.3
affected

Default status
unaffected

5bd90bb5cf0d15e375edc2a66fa322292940fce2 (git) before 340f75b5d191dc747ef7ac6365bd002d1cd55a9d
affected

Credits

Peter Ullrich finder

Yordis Prieto remediation developer

Jonatan Männchen analyst

References

github.com/.../tesla/security/advisories/GHSA-mc85-72gr-vm9f exploit

github.com/.../tesla/security/advisories/GHSA-mc85-72gr-vm9f vendor-advisory related

cna.erlef.org/cves/CVE-2026-48594.html related

osv.dev/vulnerability/EEF-CVE-2026-48594 related

github.com/...ommit/340f75b5d191dc747ef7ac6365bd002d1cd55a9d patch

cve.org (CVE-2026-48594)

nvd.nist.gov (CVE-2026-48594)

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