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.
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.
Update fluent-plugin-s3 to 1.8.5 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanfluent-plugin-s3 Vulnerable to Denial of Service (DoS) via Decompression Bomb in `in_s3` affects fluent-plugin-s3 (rubygems). Severity is low. 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.
AI coding agents often install or upgrade packages automatically in rubygems. A low vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| fluent-plugin-s3rubygems | >=0.7.0,<=1.8.4 | 1.8.5 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate fluent-plugin-s3 to 1.8.5 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanfluent-plugin-s3 Vulnerable to Denial of Service (DoS) via Decompression Bomb in `in_s3` affects fluent-plugin-s3 (rubygems). Severity is low. 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.
AI coding agents often install or upgrade packages automatically in rubygems. A low vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| fluent-plugin-s3rubygems | >=0.7.0,<=1.8.4 | 1.8.5 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard