CVE-2021-43203
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is...
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.
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
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.
- Record
CVE-2021-43203- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-287
- Updated
- 2026-11-02
CVE List No score
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.
- Record
CVE-2021-43203- Updated
- 2026-11-02
EUVDEUVD-2021-30147 No score
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.
- Record
EUVD-2021-30147- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p34x-8gxh-mj58 No score
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is...
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.
- Record
GHSA-p34x-8gxh-mj58- Weakness
- CWE-287
- Updated
- 2026-11-02
OSV
In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.
- Record
CVE-2021-43203- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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-2021-43203 is a high vulnerability (CVSS 7.5) in Jetbrains Ktor, published November 9, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.86%, the 58th percentile. No source names a fixed version.