fluent-plugin-s3: Denial of Service (DoS) via Decompression Bomb in `in_s3` (CVE-2026-44162) | HOL Guard CVE

Low · CVSS 2.7CVE-2026-44162GHSA-XV9W-7V6Q-HPJH

fluent-plugin-s3: Denial of Service (DoS) via Decompression Bomb in `in_s3`

Answer in brief

CVE-2026-44162 records a Low severity (CVSS 2.7) vulnerability in fluent-plugin-s3: Denial of Service (DoS) via Decompression Bomb in `in_s3`. The current sources do not mark it as known exploited. The current feed maps fluent/fluent-plugin-s3 (generic), fluent-plugin-s3 (rubygems), fluent-plugin-s3 (rubygems). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 14, 2026Updated Sep 14, 2026Source checked Sep 14, 2026First seen by HOL Jun 26, 2026Material review Sep 14, 2026

Upstream Advisory

Key facts

Risk: Low · CVSS 2.7
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 2.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps fluent/fluent-plugin-s3 (generic), fluent-plugin-s3 (rubygems), fluent-plugin-s3 (rubygems). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
fluent/fluent-plugin-s3generic	>= 0.7.0, < 1.8.5	Not reported
fluent-plugin-s3rubygems	>=0.7.0,<=1.8.4	1.8.5
fluent-plugin-s3rubygems	>=0.7.0 <1.8.5	1.8.5

Recommended response

Check inventory. Check lockfiles and deployed manifests for fluent/fluent-plugin-s3, fluent-plugin-s3, fluent-plugin-s3.
Review the reported fix. Update fluent-plugin-s3 to 1.8.5; fluent-plugin-s3 to 1.8.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 26, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.