CISA KEV catalog
Confirmed active exploitation.
Listed in CISA's catalog of Known Exploited Vulnerabilities: attackers are using it in real attacks. Patch it with priority.
- Name
- Fortra Cobalt Strike Teamserver Cross-Site Scripting (XSS) Vulnerability
- Added to catalog
- Remediation due date (US federal)
- Required action
- Apply updates per vendor instructions.
Description
An XSS (Cross Site Scripting) vulnerability was found in HelpSystems Cobalt Strike through 4.7 that allowed a remote attacker to execute HTML on the Cobalt Strike teamserver. To exploit the vulnerability, one must first inspect a Cobalt Strike payload, and then modify the username field in the payload (or create a new payload with the extracted information and then modify that username field to be malformed).
Affected products
helpsystems: cobalt strike
References5
- www.cobaltstrike.com/blog/out-of-band-update-cobalt-strike-4-7-… MitigationVendor Advisory
- www.cobaltstrike.com/blog/tag/release/ Release NotesVendor Advisory
- www.cobaltstrike.com/blog/out-of-band-update-cobalt-strike-4-7-… MitigationVendor Advisory
- www.cobaltstrike.com/blog/tag/release/ Release NotesVendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=… US Government Resource
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - EPSS — exploit probability
- 44% percentile: 99 · as of 2 November 2026
- CWE
- CWE-79