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TI-2026-85859 Aliases CVE-2026-123318GHSA-6mmc-8ffm-69rw

HTTP request smuggling in JetBrains Ktor CIO engine

Priority LOW 21CWE-444Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

JetBrains Ktor before 3.6.1 is affected. An inconsistent interpretation of HTTP requests (CWE-444) in the CIO engine makes HTTP request smuggling possible. An unauthenticated remote attacker with low attack complexity can cause a limited loss of confidentiality and integrity, and the vulnerability is not known to be exploited.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

In JetBrains Ktor before 3.6.1 hTTP request smuggling was possible in the CIO engine

Why it matters now

EPSS 0.00146 3rd percentileScored 2026-11-07
Fix Fixed Ktor (JetBrains): 3.6.1

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
JetBrainsKtorbefore 3.6.13.6.1Patch availableCNA
  • Ktor VendorJetBrains Affected before 3.6.1 Fixed in 3.6.1 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:jetbrains:ktor:*:*:*:*:*:*:*:*——JetBrains
  • cpe:2.3:a:jetbrains:ktor:*:*:*:*:*:*:*:* Versions — — ·JetBrains

Remediation

Update JetBrains Ktor to version 3.6.1 or later.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Ktor (JetBrains) Fixed in 3.6.1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    JetBrains Ktor 3.6.1

    3 records Highest priority Priority LOW 3 LOW

    Other records, highest priority first

    • TI-2026-85858 Session forgery in JetBrains Ktor via tampered encrypted session cookiesPriority LOW 37
    • TI-2026-85860 Cookie injection in JetBrains Ktor client cookie storagePriority LOW 17
    Show all 3 records →

Timeline

  1. 2026-11-06 Threatist record created from CVE-2026-123318
  2. 2026-11-06 Alias added: GHSA-6mmc-8ffm-69rw

References

Other 1

  • TI-2026-45031 Deserialization of untrusted data in JetBrains TeamCity KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-18053 In JetBrains TeamCity before 2023.11.4 authentication bypass allowing to perform admin actions was possible KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-22884 In JetBrains TeamCity before 2023.05.4 authentication bypass leading to RCE on TeamCity Server was possible KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-18054 In JetBrains TeamCity before 2023.11.4 path traversal allowing to perform limited admin actions was possible KEVCVSS 3.1HIGH 7.3
  • TI-2024-15905 In JetBrains TeamCity before 2023.11.3 authentication bypass leading to RCE was possible CVSS 3.1CRITICAL 9.8
  • TI-2024-24589 Insufficiently protected credentials in JetBrains IntelliJ IDEA CVSS 3.1CRITICAL 9.3
See all 787 →

Sources

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