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.
- 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 sourcePublished 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"
}