CVE-2026-108714MCP Kotlin SDK through 0.15.0 Memory Exhaustion via Application.mcpWebSocket
Updated under an hour ago ()
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It affects modelcontextprotocol kotlin-sdk. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.36%, higher than 28% of scored CVEs.
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MCP Kotlin SDK through 0.15.0 contains an uncontrolled memory allocation vulnerability that allows remote clients to exhaust server memory because Application.mcpWebSocket installs Ktor WebSockets without a maxFrameSize limit. Attackers can send small frame headers declaring payloads near 2 GiB over one or a few connections, forcing huge heap allocations and causing denial of service.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.36% (percentile 28)
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 11, 2026
Affected products
modelcontextprotocol kotlin-sdk modelcontextprotocol:kotlin_sdk (from the name) | through 0.15.0 | CNA record |
References
- https://hackmd.io/@haind/mcp-kotlin-sdk-websocket-frame-allocation-dosthird-party-advisory
- https://github.com/modelcontextprotocol/kotlin-sdk/blob/0.15.0/kotlin-sdk-server/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/server/WebSocketMcpKtorServerExtensions.kt#L41-L63technical-description
- https://github.com/modelcontextprotocol/kotlin-sdk/blob/0.15.0/kotlin-sdk-core/src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/WebSocketMcpTransport.kt#L60-L85technical-description
- https://github.com/modelcontextprotocol/kotlin-sdkproduct
- https://www.vulncheck.com/advisories/mcp-kotlin-sdk-through-0.15.0-memory-exhaustion-via-application-mcpwebsocketthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.