CVE-2026-42270

countly-server: Unauthenticated Denial of Service (DoS) via Unhandled Stream Exception

HIGH
7.5
CVSS Score
Published: October 16, 2026 at 04:02 PM UTC
Updated: October 16, 2026 at 08:02 PM UTC
1 product affected across 1 vendorCountly Server

Using countly-server by Countly?

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 24.05.50>= 25.03, < 25.03.44

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-248

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