CVE-2026-19671Network attack vector

Authenticated disk exhaustion via unchecked decompression

Published Aug 18, 2026 · Updated Aug 18, 2026

Denial of service in Malcolm through 26.07.1 allows remote authenticated users to interrupt service via crafted compressed uploads. In scripts/safe-extract.py, the upload pipeline applies entry-count, nesting-depth, and total-uncompressed-byte limits to container archives, but decompresses standalone .gz, .bz2, .xz, .lzma, and .lz inputs without an equivalent output-size cap. Any account allowed to upload PCAP or log files can expand a small gzip-bomb-style file into unbounded data on the shared Docker volume, disrupting OpenSearch, Logstash, Arkime, and Zeek for other users.

CVSS severity7.1
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Malcolm through 26.07.1 allows remote authenticated users to interrupt service via crafted compressed uploads. In scripts/safe-extract.py, the upload pipeline applies entry-count, nesting-depth, and total-uncompressed-byte limits to container archives, but decompresses standalone .gz, .bz2, .xz, .lzma, and .lz inputs without an equivalent output-size cap. Any account allowed to upload PCAP or log files can expand a small gzip-bomb-style file into unbounded data on the shared Docker volume, disrupting OpenSearch, Logstash, Arkime, and Zeek for other users.

The record

CVE
CVE-2026-19671
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Cybersecurity and Infrastructure Security Agency (CISA)
Product
Malcolm
Classifications
CWE-409, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=26.07.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cybersecurity and Infrastructure Security Agency (CISA) · Malcolmversion=0 <=26.07.1

Published CVSS scores

7.1GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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