CVE-2026-19671
Received Received - Intake

Denial of Service in Malcolm Upload Pipeline via Compressed File

Publication date: 2026-08-18

Last updated on: 2026-08-18

Assigner: ICS-CERT

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.

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Meta Information

Published
2026-08-18
Last Modified
2026-08-18
Generated
2026-08-19
AI Q&A
2026-08-18
EPSS Evaluated
N/A
NVD
CVE-2026-19671
EUVD
EUVD-2026-61160

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
opensearch opensearch *
logstash logstash *
arkime arkime *
zeek zeek *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-409 The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.

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Executive Summary

This vulnerability involves Malcolm's upload-processing pipeline not enforcing size limits when extracting single-stream compressed files like .gz or .bz2. An attacker can upload a small, highly compressible file that decompresses to an extremely large size, consuming disk space and disrupting the platform for all users.

Detection Guidance

Monitor disk usage on the shared Docker volume used by OpenSearch, Logstash, Arkime, and Zeek. Check for unusually large decompressed files from single-stream compressed formats like .gz, .bz2, .xz, .lzma, or .lz. Look for rapid disk space exhaustion or high I/O activity during upload processing.

Impact Analysis

If you use Malcolm's platform, this vulnerability could cause service disruption by exhausting disk space on the shared Docker volume. All users relying on OpenSearch, Logstash, Arkime, and Zeek would be affected, leading to potential downtime or data loss.

Mitigation Strategies

Apply the same entry-count, nesting-depth, and total-uncompressed-byte limits to single-stream compressed formats in the upload-processing pipeline. Restrict authenticated users' upload permissions to only necessary roles. Monitor and enforce disk space quotas on the shared Docker volume.

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