Vulnerability · Published Aug 18, 2026 · Assigned by icscert
CVE-2026-19671Improper handling of highly compressed data (data amplification) in CISA Malcolm
Medium 6.5
In plain English
A medium-severity security flaw in Malcolm from CISAgov. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).
Official description
Malcolm's upload-processing pipeline (scripts/safe-extract.py) enforces entry-count, nesting-depth, and total-uncompressed-byte limits when extracting container archives (zip/tar/rar/7z via libarchive), but those limits are not applied when the uploaded file is a single-stream compressed format (.gz, .bz2, .xz, .lzma, .lz) that isn't a .tar.*-style archive. Any authenticated user permitted to upload PCAP/log files can upload a small, highly compressible file (e.g. a gzip bomb) that decompresses to an effectively unbounded size on disk, exhausting the shared Docker volume used by OpenSearch, Logstash, Arkime, and Zeek, and disrupting the platform for all users.
Affected products (as reported)
Weakness: CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H