high7.5
CVE-2026-108859
mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memor…
Impact
mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sending oversized POST bodies. Attackers can send arbitrarily large or many concurrent POST requests, read fully via io.ReadAll before validation, to degrade or OOM-kill the server process.
Affected products
| Product | Affected versions |
|---|---|
| Mcp-Go | through 1.2.1 |
Versions were read from the advisory text. No structured product data has been published for this record yet.
Weakness classification
References
- NVD record
- CVE.org record
- https://github.com/mark3labs/mcp-go
- https://github.com/mark3labs/mcp-go/blob/90d247ed8d45cbb7d71d9a95e112789b78760443/server/streamable_http.go#L405-L411
- https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/mark3labs-mcp-go-streamable-http-unbounded-body
- https://www.vulncheck.com/advisories/mcp-go-through-1.2.1-denial-of-service-via-unbounded-post-body-buffering