---
title: "CVE-2026-44024: Fluentd is Vulnerable to Remote Code Execution (RCE) via Arbitrary File Write in `${tag}` Placeholder"
url: https://erroneo.us/security/cve/CVE-2026-44024/
description: "CVE-2026-44024 (fluentd (RubyGems)): Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on.…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-08
date_modified: 2026-07-10
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-44024"
kev: false
cvss: 9.8
epss: 0.01085
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-44024: Fluentd is Vulnerable to Remote Code Execution (RCE) via Arbitrary File Write in `${tag}` Placeholder

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.1% , percentile 65: FIRST’s model estimates a 1.1% chance of exploitation activity in the next 30 days, higher than 65% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes fluentd (RubyGems) <= 1.19.2, fixed in 1.19.3 . Check your lockfile, including transitive dependencies.

## What it is

Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on. Prior to 1.19.3, Fluentd allows dynamically constructing file paths using the ${tag} placeholder, and insufficient validation of ${tag} in file configurations such as the path parameter of the outfile plugin allows attackers sending untrusted tags containing path traversal characters to write or overwrite arbitrary files and potentially achieve remote code execution. This issue is fixed in version 1.19.3.

## Affected packages

- RubyGems `fluentd` <= 1.19.2 → fixed: 1.19.3

## Affected products (CVE record)

- fluent fluentd: < 1.19.3

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.08% probability of exploitation activity in the next 30 days; percentile 65.

## Sources

- [GitHub Advisory GHSA-44hj-4m45-frj3](https://github.com/advisories/GHSA-44hj-4m45-frj3)
- [CVE.org record CVE-2026-44024](https://www.cve.org/CVERecord?id=CVE-2026-44024)
- [NVD entry CVE-2026-44024](https://nvd.nist.gov/vuln/detail/CVE-2026-44024)
- [github.com](https://github.com/fluent/fluentd/security/advisories/GHSA-44hj-4m45-frj3)
- [github.com](https://github.com/fluent/fluentd/pull/5391)
- [github.com](https://github.com/fluent/fluentd/commit/45c87a81f3ac0b72b3f9dcfe8cfb5f9038f81437)
- [github.com](https://github.com/fluent/fluentd/releases/tag/v1.19.3)

---
Source page: https://erroneo.us/security/cve/CVE-2026-44024/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt