Vulnerability · Published Nov 5, 2026 · Assigned by EEF
CVE-2026-119434Decompression bomb in ezstd:decompress_using_ddict/2 allows BEAM memory exhaustion via unbounded output buffer
Medium 6.2
In plain English
A medium-severity security flaw in ezstd from silviucpp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities).
Official 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.
Affected products (as reported)
Weakness: CWE-409 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- ezstd v1.2.5 release notes release-notes, related
- EEF CNA record for CVE-2026-119434 related, third-party-advisory
- OSV record EEF-CVE-2026-119434 related
- Introducing commit 6730128 in silviucpp/ezstd related
- Fix commit e34f4a4 in silviucpp/ezstd patch