---
id: CVE-2026-44162
title: fluent-plugin-s3 is an Amazon S3 input and output plugin for Fluentd
summary: >-
  fluent-plugin-s3 is an Amazon S3 input and output plugin for Fluentd. From
  0.7.0 to 1.8.4, the in_s3 input plugin reads the entire decompressed payload
  of gzip, lzma2, and lzop objects into memory without enforcing a
  decompression_size_l…
severity: low
cvss: 2.7
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-409
  - CWE-770
vendor: fluent
product: fluent-plugin-s3
affected:
  - 'fluent-plugin-s3 >= 0.7.0, < 1.8.5'
patched:
  - fluent-plugin-s3 1.8.5
published: '2026-09-14'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T19:17:21.570'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-44162'
references:
  - url: >-
      https://github.com/fluent/fluent-plugin-s3/commit/e085aee001d15bcc4bd073507e74075e30550fd0
    label: security-advisories@github.com
  - url: 'https://github.com/fluent/fluent-plugin-s3/releases/tag/v1.8.5'
    label: security-advisories@github.com
  - url: >-
      https://github.com/fluent/fluent-plugin-s3/security/advisories/GHSA-xv9w-7v6q-hpjh
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-xv9w-7v6q-hpjh'
tags:
  - nvd
  - cve.org
  - ghsa
  - rubygems
ecosystem: rubygems
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-14T18:14:06.116972Z'
ingestedAt: '2026-06-29T13:24:35.297Z'
epss: 0.00483
epssPercentile: 0.38969
---

## Overview

fluent-plugin-s3 is an Amazon S3 input and output plugin for Fluentd. From 0.7.0 to 1.8.4, the in_s3 input plugin reads the entire decompressed payload of gzip, lzma2, and lzop objects into memory without enforcing a decompression_size_limit. An attacker with permission to upload objects to the monitored S3 bucket can provide a highly compressed object that expands excessively when Fluentd processes it. The resulting memory exhaustion can cause the operating system to terminate the Fluentd process and disrupt all log collection on the affected node. This issue is fixed in version 1.8.5.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-44162)

Affected packages:

- `fluent-plugin-s3 >= 0.7.0, <= 1.8.4`

Patched in:

- `fluent-plugin-s3 1.8.5`

Source: https://github.com/advisories/GHSA-xv9w-7v6q-hpjh