Medium · CVSS 6.9CVE-2026-119434

Decompression bomb in ezstd:decompress_using_ddict/2 allows BEAM memory exhaustion via unbounded output bufferCVE-2026-119434

Answer in brief

CVE-2026-119434 records a Medium severity (CVSS 6.9) vulnerability in Decompression bomb in ezstd:decompress_using_ddict/2 allows BEAM memory exhaustion via unbounded output buffer. The current sources do not mark it as known exploited. The current feed maps silviucpp/ezstd (generic), silviucpp/silviucpp/ezstd (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Nov 5, 2026Updated Nov 5, 2026Source checked Nov 5, 2026First seen by HOL Nov 5, 2026Material review Nov 5, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.9
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps silviucpp/ezstd (generic), silviucpp/silviucpp/ezstd (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
silviucpp/ezstdgeneric	>=1.0.5 <1.2.5	1.2.5
silviucpp/silviucpp/ezstdgeneric	>=6730128b1d35eca02a2028671421471ff651f423 <e34f4a4f6dc18d990d1cece2d5fceef8e934a195	e34f4a4f6dc18d990d1cece2d5fceef8e934a195

Recommended response

Check inventory. Check lockfiles and deployed manifests for silviucpp/ezstd, silviucpp/silviucpp/ezstd.
Review the reported fix. Source-reported 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.

Evidence timeline and material changes

Published upstream
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Nov 5, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Affected scope and exposure questions

The current feed maps silviucpp/ezstd (generic), silviucpp/silviucpp/ezstd (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
silviucpp/ezstdgeneric	>=1.0.5 <1.2.5	1.2.5
silviucpp/silviucpp/ezstdgeneric	>=6730128b1d35eca02a2028671421471ff651f423 <e34f4a4f6dc18d990d1cece2d5fceef8e934a195	e34f4a4f6dc18d990d1cece2d5fceef8e934a195

Recommended response

Check inventory. Check lockfiles and deployed manifests for silviucpp/ezstd, silviucpp/silviucpp/ezstd.

Review the reported fix. Source-reported 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.

Sources and claim methodology

Upstream source description

Quoted source text, attributed separately from HOL analysis.