Bug 2567737 (CVE-2026-119434)

Summary: CVE-2026-119434 ezstd: ezstd: Denial of Service via memory exhaustion during decompression
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in ezstd. An attacker can cause a Denial of Service (DoS) by providing a specially crafted compressed data frame that declares an excessively large uncompressed size. When decompressing the data using a dictionary, ezstd fails to enforce memory buffer limits, leading to memory exhaustion that causes the operating system to terminate the Erlang virtual machine.
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Description OSIDB Bzimport 2026-11-05 22:22:12 UTC 
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.