Improper handling of highly compressed data (data amplification) in CISA Malcolm
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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-19670US | —OT elevated | — | ||
Malcolm's nginx Lua role-based access control (RBAC) layer decides whether an authenticated user may reach a role-restricted path (e.g. /htadmin, /auth, /admin_login, /arkime/api/e… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19671.jsonADVISORY
- https://github.com/cisagov/Malcolm/security/advisories/GHSA-f2v6-8cj4-mhr6ADVISORY
- https://nvd.nist.gov/vuln/detail/CVE-2026-19671ADVISORY
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01ADVISORY
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