Critical severity · published Oct 16, 2026
CVE-2026-44977
countly-server: Stored XSS in feedback upload enables app-admin to compromise global admin session context
9.0
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
countly-server · Countly
< 24.05.50; >= 25.03, < 25.03.44 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44977
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-44977
github.com
https://github.com/Countly/countly-server/commit/ae899f37bc6d70c1b44859756ce80a204ae72631
github.com
https://github.com/Countly/countly-server/commit/fcb16c808c0fdb6dc99fe9c66de7fc560b3a9c41
github.com
https://github.com/Countly/countly-server/releases/tag/24.05.50
github.com
https://github.com/Countly/countly-server/releases/tag/25.03.44
github.com
https://github.com/Countly/countly-server/security/advisories/GHSA-jqp4-p86c-phxc
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