Skip to content
Heist/ feed
Back to feed
High

Improper handling of highly compressed data (data amplification) in CISA Malcolm

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-19670, CVE-2026-19671
Confirmed fixed CVEs
Not specified
Updated in this feed
7 Nov 2026, 09:19 UTC · Revision 1

Source evidence

Improper handling of highly compressed data (data amplification) in CISA Malcolm

core-osv · Original source

Published 18 Aug 2026, 19:11 UTC

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.

osv:CVE-2026-19671
Complete source record
{
  "id": "b5f9953216612e78c4d900e11b42288e4fa45243e6417f8e94d420d17b9dfc0e",
  "url": "https://osv.dev/vulnerability/CVE-2026-19671",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Improper handling of highly compressed data (data amplification) in CISA Malcolm",
    "summary": "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.",
    "evidence": "osv:CVE-2026-19671",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-19671",
      "aliases": [
        "CVE-2026-19670",
        "CVE-2026-19671",
        "GHSA-f2v6-8cj4-mhr6"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/cisagov/malcolm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "2c19ef04d85230634ac70cc68b8f418a0666afec"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "26.07.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v26.07.1",
            "v26.07.0",
            "v26.06.1",
            "v26.06.0",
            "v26.05.2",
            "v6.4.2",
            "v6.4.1",
            "v6.4.0",
            "v5.2.4",
            "v5.2.3",
            "v5.2.2",
            "v5.2.1",
            "v3.0.1",
            "v3.0.0",
            "v2.6.1",
            "v2.6.0",
            "v2.5.0",
            "v2.4.2",
            "v2.4.1",
            "v2.4.0.1",
            "v2.4.0",
            "v2.3.0",
            "v2.2.1",
            "v2.2.0",
            "v2.1.1",
            "v2.1.0",
            "v2.0.6",
            "v2.0.5",
            "v2.0.4",
            "v2.0.3",
            "v2.0.2",
            "v2.0.1",
            "v2.0.0",
            "v2.0.0-pre1",
            "v1.8.1",
            "v1.8.0",
            "v1.7.2",
            "v1.7.1a",
            "v1.7.1",
            "v1.7.0",
            "v1.6.0",
            "v1.5.2",
            "v1.5.1",
            "v1.5.0",
            "v1.4.0",
            "v1.3.1",
            "v1.3.0",
            "v1.2.2",
            "v1.2.1",
            "v1.2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-19671.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.377292067Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19671.json",
        "https://github.com/cisagov/Malcolm/security/advisories/GHSA-f2v6-8cj4-mhr6",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-19671",
        "https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-409"
        ],
        "cna_assigner": "icscert",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19671.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-19670",
        "evidence": "/aliases"
      },
      {
        "value": "CVE-2026-19671",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518864,
  "published_at": "2026-08-18T19:11:58.23+00:00"
}