countly-server: Stored XSS in feedback upload enables app-admin to compromise global admin session context
CVE-2026-44977 · published 16 Oct 2026
How serious is it
- Severity: critical, CVSS score 9 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-44977?
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Who is affected
- Countly countly-server: < 24.05.50, >= 25.03, < 25.03.44
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
countly-server is the server-side part of Countly, a product analytics solution. Prior to 24.05.50 and 25.03.44, plugins/star-rating/api/api.js allows a non-global application administrator to use uploadFeedbackFile to store attacker-controlled active content while trusting the supplied MIME type. plugins/star-rating/frontend/app.js publicly serves the stored content from feedback/preview/ with the attacker-influenced Content-Type, so a global administrator who opens the preview executes the payload in the Countly origin and exposes authenticated session capabilities, including auth_token and csrf_token values. This issue is fixed in versions 24.05.50 and 25.03.44.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- github.com/Countly/countly-server/security/advisories/GHSA-jqp4-p86c-phxc
- github.com/Countly/countly-server/commit/ae899f37bc6d70c1b44859756ce80a204ae72631
- github.com/Countly/countly-server/commit/fcb16c808c0fdb6dc99fe9c66de7fc560b3a9c41
- github.com/Countly/countly-server/releases/tag/24.05.50
- github.com/Countly/countly-server/releases/tag/25.03.44
Merged from CVE List. Last updated 24 Oct 2026. All vulnerabilities · RSS · JSON