CVE-2026-42270
countly-server: Unauthenticated Denial of Service (DoS) via Unhandled Stream Exception
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
countly-server: Unauthenticated Denial of Service (DoS) via Unhandled Stream Exception
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.
- Record
CVE-2026-42270- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-248
- Updated
- 2026-11-02
EUVDEUVD-2026-102916
7.5
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.
- Record
EUVD-2026-102916- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
NVD
7.5
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.
- Record
CVE-2026-42270- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-248
- Updated
- 2026-11-02
OSV
7.5
countly-server: Unauthenticated Denial of Service (DoS) via Unhandled Stream Exception
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.
- Record
CVE-2026-42270- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-248
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-42270 is a high vulnerability (CVSS 7.5) in Countly Countly-server, published October 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.54%, the 45th percentile. No source names a fixed version.
References
github.com/Countly/countly-server/security/advisories/GHSA-86cv-qwp9-jwp3
github.com/Countly/countly-server/commit/72f19bc5161117fa02a224bf9f7316bf42dae58d
github.com/Countly/countly-server/commit/f9ad31480f94ee3ccc0f12708c8804be9c803f95
github.com/Countly/countly-server/releases/tag/24.05.50
github.com/Countly/countly-server/releases/tag/25.03.44
github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42270.json
nvd.nist.gov/vuln/detail/CVE-2026-42270