fluent-plugin-s3 Vulnerable to Denial of Service (DoS) via Decompression Bomb in `in_s3` (CVE-2026-44162)
fluent-plugin-s3 versions from 0.7.0 up to but not including 1.8.5 contain a vulnerability in the in_s3 input plugin where decompressed payloads from gzip, lzma2, and lzop objects are fully loaded into memory without size limits. This can allow an attacker with upload permissions to supply a compressed object that expands excessively, causing memory exhaustion and potential termination of the Fluentd process, disrupting log collection. The issue is fixed in version 1.8.5.
AI Analysis
Technical Summary
The fluent-plugin-s3 input plugin in versions >=0.7.0 and <1.8.5 reads the entire decompressed payload of certain compressed objects (gzip, lzma2, lzop) into memory without enforcing a decompression size limit. An attacker who can upload objects to the monitored S3 bucket can exploit this by providing a decompression bomb—an object that decompresses to a very large size—leading to memory exhaustion. This exhaustion can cause the operating system to terminate the Fluentd process, resulting in denial of service by disrupting log collection on the affected node. The vulnerability is tracked as CVE-2026-44162 and has a low CVSS score of 2.7. The issue is resolved in version 1.8.5.
Potential Impact
Successful exploitation results in denial of service due to memory exhaustion causing the Fluentd process to be terminated by the operating system. This disrupts log collection on the affected node. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade fluent-plugin-s3 to version 1.8.5 or later where this vulnerability is fixed. No other mitigations are indicated.
fluent-plugin-s3 Vulnerable to Denial of Service (DoS) via Decompression Bomb in `in_s3` (CVE-2026-44162)
Description
fluent-plugin-s3 versions from 0.7.0 up to but not including 1.8.5 contain a vulnerability in the in_s3 input plugin where decompressed payloads from gzip, lzma2, and lzop objects are fully loaded into memory without size limits. This can allow an attacker with upload permissions to supply a compressed object that expands excessively, causing memory exhaustion and potential termination of the Fluentd process, disrupting log collection. The issue is fixed in version 1.8.5.
CVSS v3.1
Score 2.7low
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The fluent-plugin-s3 input plugin in versions >=0.7.0 and <1.8.5 reads the entire decompressed payload of certain compressed objects (gzip, lzma2, lzop) into memory without enforcing a decompression size limit. An attacker who can upload objects to the monitored S3 bucket can exploit this by providing a decompression bomb—an object that decompresses to a very large size—leading to memory exhaustion. This exhaustion can cause the operating system to terminate the Fluentd process, resulting in denial of service by disrupting log collection on the affected node. The vulnerability is tracked as CVE-2026-44162 and has a low CVSS score of 2.7. The issue is resolved in version 1.8.5.
Potential Impact
Successful exploitation results in denial of service due to memory exhaustion causing the Fluentd process to be terminated by the operating system. This disrupts log collection on the affected node. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
Upgrade fluent-plugin-s3 to version 1.8.5 or later where this vulnerability is fixed. No other mitigations are indicated.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-xv9w-7v6q-hpjh
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-44162"]
- Ecosystems
- ["RubyGems"]
- Database Specific Severity
- LOW
- Cvss Version
- 3.1
Threat ID: 6a3ef79427e9c79719ff8d69
Added to database: 06/26/2026, 22:05:08 UTC
Last enriched: 09/14/2026, 22:13:21 UTC
Last updated: 09/14/2026, 22:13:21 UTC
Views: 110
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