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TI-2021-19215 Aliases CVE-2021-43203GHSA-p34x-8gxh-mj58

In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.

Priority LOW 34CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-287.

Summary

In JetBrains Ktor before 1.6.4, nonce verification during the OAuth2 authentication process is implemented improperly.

Why it matters now

EPSS 0.00864 58th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:jetbrains:ktor:*:*:*:*:*:*:*:*before 1.6.4VulnerableJetBrains
  • cpe:2.3:a:jetbrains:ktor:*:*:*:*:*:*:*:* Versions before 1.6.4 Vulnerable ·JetBrains

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-43203
  2. 2026-10-03 Alias added: GHSA-p34x-8gxh-mj58

References

Advisory 1

  • TI-2023-24413 In JetBrains Ktor before 2.3.5 default configuration of ContentNegotiation with XML format was vulnerable to XXE CVSS 3.1CRITICAL 9.8
  • TI-2019-09527 JetBrains Ktor framework before 1.2.0-rc does not sanitize the username provided by the… CVSS 3.1CRITICAL 9.8
  • TI-2023-24414 In JetBrains Ktor before 2.3.5 server certificates were not verified CVSS 3.1CRITICAL 9.1
  • TI-2022-24056 In JetBrains Ktor before 2.3.0 path traversal in the `resolveResource` method was possible CVSS 3.1HIGH 7.5
  • TI-2022-12277 SHA1 implementation in JetBrains Ktor Native 2.0.0 was returning the same value. CVSS 3.1HIGH 8.7
  • TI-2019-07426 JetBrains Ktor framework (created using the Kotlin IDE template) versions before 1.1.0… CVSS 3.0HIGH 8.1
See all 20 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences