🛡️ CVE-2026-44162 — fluent-plugin-s3

🟢 CVSS 2.0 — Low ✅ No Known Exploit CWE-770 OSV
2.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

fluent-plugin-s3 Vulnerable to Denial of Service (DoS) via Decompression Bomb in in_s3

The fluent-plugin-s3 plugin (specifically the in_s3 input plugin) supports reading and decompressing heavily compressed files (such as gzip, lzma2, and lzop) from Amazon S3.

It was discovered that the plugin read the entire decompressed payload into memory at once without enforcing a strict size limit.

If an attacker has sufficient permissions to upload files to the monitored S3 bucket, they can upload a maliciously crafted, highly compressed file.

When Fluentd attempts to decompress this file, it will expand to an excessive size and it will consume significant system resources.

Impact

This vulnerability allows for a Denial of Service (DoS) attack via memory exhaustion.

The rapid memory consumption during decompression can lead to an Out-of-Memory kill of the Fluentd process by the operating system,

This results in the disruption of all log collection on the affected node.

Patches

v1.8.5

Workarounds

If an immediate upgrade is not possible, mitigate the risk by applying strict IAM access controls:

1. Restrict Bucket Access

  • Ensure that write (PUT) access to the S3 bucket monitored by in_s3 is strictly limited to trusted services and administrators. Prevent any public or untrusted uploads to the S3 bucket.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs administrative privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability low.

Weakness class

CVE-2026-44162 is classified as CWE-770: Allocation of Resources Without Limits. Resources are allocated on request with no cap, so a client can exhaust them.

Affected software

CVE-2026-44162 is recorded against 1 package.

  • fluent-plugin-s3 (from 0.7.0 up to 1.8.5)

Timeline and source

Published on 26 June 2026 and last revised on 3 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
github.com (Package)

Details

Severity LOW
CVSS Score 2.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
CWE CWE-770
Public Exploit ✅ No
Source OSV
Published 2026-06-26
Updated 2026-08-20
Modified 2026-07-03
Fix URL N/A

Affected Packages

Software From version Fixed in
fluent-plugin-s3 0.7.0 1.8.5

Similar Threats

Free Vulnerability Check

Is your site affected by CVE-2026-44162?

BotEraser helps you identify potentially vulnerable plugins and themes by checking your installation against CVE-2026-44162 and other known CVE records.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesCVECVE 2026