CVE-2021-3646
Cross-site Scripting (XSS) - Reflected in btcpayserver/btcpayserver
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Cross-site Scripting (XSS) - Reflected in btcpayserver/btcpayserver
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
CVE-2021-3646- CVSS 3.0
- 4.9 Medium
CVSS:3.0/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-26943
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
EUVD-2021-26943- CVSS 3.0
- 4.9 Medium
CVSS:3.0/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p4ww-48c6-98q5 No score
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross...
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
GHSA-p4ww-48c6-98q5- Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
CVE-2021-3646- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 3.0
- 4.9 Medium
CVSS:3.0/AV:A/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
CVE-2021-3646- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3646 is a medium vulnerability (CVSS 4.9) in Btcpayserver Btcpayserver/btcpayserver, published September 10, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.77%, the 55th percentile. No source names a fixed version.