CVE-2026-44160Network attack vector

Service crash via unbounded gzip decompression

Published Jul 8, 2026 · Updated Jul 8, 2026

Improper compressed-data handling in Fluentd before 1.19.3 allows remote attackers to crash the process via crafted gzip input. The in_http and in_forward plugins limit only the compressed body or chunk, then inflate attacker-controlled data in memory without bounding the decompressed size. An instance must expose either input to an untrusted network; exhaustion can trigger an operating-system out-of-memory kill and halt log collection and forwarding.

CVSS severity7.5
High
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper compressed-data handling in Fluentd before 1.19.3 allows remote attackers to crash the process via crafted gzip input. The in_http and in_forward plugins limit only the compressed body or chunk, then inflate attacker-controlled data in memory without bounding the decompressed size. An instance must expose either input to an untrusted network; exhaustion can trigger an operating-system out-of-memory kill and halt log collection and forwarding.

The record

CVE
CVE-2026-44160
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Fluentd
Product
Fluentd
Classifications
CWE-409, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 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=< 1.19.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fluentd · Fluentdversion=< 1.19.3

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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