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VulnerabilityPublished

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

Affects fluent-plugin-s3Source GCVE Database

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Authoritative record:CVE-2026-44162· Low 2.7

Not known to be exploited · CVSS 2.7 Low : upgrade to 1.8.5 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
2.7Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.8.5
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade fluent-plugin-s3 to 1.8.5.

Affected software

ProductAffectedFixed in
RubyGemsfluent-plugin-s3Affected
  • >=0.7.0 <1.8.5
Fixed in
  • 1.8.5

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade fluent-plugin-s3 to version 1.8.5 or later where this vulnerability is fixed. No other mitigations are indicated.

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.

References

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