Description
Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in silviucpp ezstd allows an attacker who supplies a zstd frame to ezstd:decompress_using_ddict/2 to exhaust memory and terminate the Erlang VM via a small frame that declares a very large content size.

zstd_nif_decompress_using_ddict in c_src/ezstd_nif.cc reads the frame's declared content size with ZSTD_getFrameContentSize and passes it directly to enif_make_new_binary, without the 1 GiB MAX_BUFFER_SIZE check that ezstd:decompress/1 applies before allocating. A valid 65,550-byte frame of RLE blocks declaring 2 GiB is rejected by ezstd:decompress/1 but is fully allocated and decompressed by the dictionary path. The allocation happens inside a NIF, so when it exceeds the memory available to the VM the operating system kills the whole node rather than the calling process.

This issue affects ezstd: from 1.0.5 before 1.2.5.
Published: 2026-11-05
Score: 6.9 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Workaround

Replace calls to ezstd:decompress_using_ddict/2 with the streaming API: create a context with ezstd:create_decompression_context/1 using a small output buffer, attach the dictionary with ezstd:select_ddict/2, and decompress with ezstd:decompress_streaming/2. The streaming path decompresses into the caller-sized buffer and gives up with {error, decompressor_stuck} after 1000 chunks, so a 64 KiB buffer caps a single call at 64 MiB of output. Treat that error as a rejected input. Legitimate frames whose output exceeds 1000 times the buffer size fail the same way, so size the buffer for the largest expected payload.

Tracking

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Advisories

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History

Thu, 05 Nov 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.2, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Thu, 05 Nov 2026 20:30:00 +0000

Type Values Removed Values Added
Description Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in silviucpp ezstd allows an attacker who supplies a zstd frame to ezstd:decompress_using_ddict/2 to exhaust memory and terminate the Erlang VM via a small frame that declares a very large content size. zstd_nif_decompress_using_ddict in c_src/ezstd_nif.cc reads the frame's declared content size with ZSTD_getFrameContentSize and passes it directly to enif_make_new_binary, without the 1 GiB MAX_BUFFER_SIZE check that ezstd:decompress/1 applies before allocating. A valid 65,550-byte frame of RLE blocks declaring 2 GiB is rejected by ezstd:decompress/1 but is fully allocated and decompressed by the dictionary path. The allocation happens inside a NIF, so when it exceeds the memory available to the VM the operating system kills the whole node rather than the calling process. This issue affects ezstd: from 1.0.5 before 1.2.5.
Title Decompression bomb in ezstd:decompress_using_ddict/2 allows BEAM memory exhaustion via unbounded output buffer
First Time appeared Silviucpp
Silviucpp ezstd
Weaknesses CWE-409
CPEs cpe:2.3:a:silviucpp:ezstd:*:*:*:*:*:*:*:*
Vendors & Products Silviucpp
Silviucpp ezstd
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-11-05T20:45:33.490Z

Reserved: 2026-10-30T10:30:01.015Z

Link: CVE-2026-119434

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-05T21:18:41.210

Modified: 2026-11-05T21:18:41.210

Link: CVE-2026-119434

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-05T21:45:05Z

Weaknesses
  • CWE-409

    Improper Handling of Highly Compressed Data (Data Amplification)