Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Checkout DevGuardView on GitHub
Search

GHSA-xv9w-7v6q-hpjh

LowCVSS 2.7 / 10
Published Jun 26, 2026·Last modified Jun 26, 2026
Affected Components(0)

No affected components available

Description

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.
Risk Scores
Base Score
2.7

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs high-level or administrative privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the availability of the system.

Threat Intelligence
2.5

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

Low severity
Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard