---
id: CVE-2026-42270
title: >-
  countly-server: Unauthenticated Denial of Service (DoS) via Unhandled Stream
  Exception
summary: >-
  countly-server is the server-side part of Countly, a product analytics
  solution. Prior to 24.05.50 and 25.03.44, star-rating/images/ and
  dashboards/images/screenshots/ are among public image and screenshot routes
  using the local fs stora…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-248
vendor: Countly
product: countly-server
affected:
  - countly-server < 24.05.50
  - 'countly-server >= 25.03, < 25.03.44'
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-16T16:52:07.011789Z'
exploitAvailable: true
published: '2026-10-16'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T16:52:38.647Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-42270'
references:
  - url: >-
      https://github.com/Countly/countly-server/security/advisories/GHSA-86cv-qwp9-jwp3
    label: >-
      https://github.com/Countly/countly-server/security/advisories/GHSA-86cv-qwp9-jwp3
  - url: >-
      https://github.com/Countly/countly-server/commit/72f19bc5161117fa02a224bf9f7316bf42dae58d
    label: >-
      https://github.com/Countly/countly-server/commit/72f19bc5161117fa02a224bf9f7316bf42dae58d
  - url: >-
      https://github.com/Countly/countly-server/commit/f9ad31480f94ee3ccc0f12708c8804be9c803f95
    label: >-
      https://github.com/Countly/countly-server/commit/f9ad31480f94ee3ccc0f12708c8804be9c803f95
  - url: 'https://github.com/Countly/countly-server/releases/tag/24.05.50'
    label: 'https://github.com/Countly/countly-server/releases/tag/24.05.50'
  - url: 'https://github.com/Countly/countly-server/releases/tag/25.03.44'
    label: 'https://github.com/Countly/countly-server/releases/tag/25.03.44'
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-10-16T17:24:46.897Z'
---

## Overview

countly-server is the server-side part of Countly, a product analytics solution. Prior to 24.05.50 and 25.03.44, star-rating/images/ and dashboards/images/screenshots/ are among public image and screenshot routes using the local fs storage backend that call getStream and pipe filesystem streams to HTTP responses without an error listener. An unauthenticated request containing a URL-encoded dot can make createReadStream open a directory, emit an asynchronous EISDIR error, and terminate the Node.js process as an unhandled exception, allowing repeated requests to keep the analytics API unavailable. The affected routes also include /appimages/*, /memberimages/*, and */screenshots/*. This issue is fixed in versions 24.05.50 and 25.03.44.

## Affected

- `countly-server < 24.05.50`
- `countly-server >= 25.03, < 25.03.44`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.