CVE-2026-108859
High
Description
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductMark3labs Mcp-go
PublishedOct 11, 2026
First seenOct 11, 2026
Weakness typeCWE-770Allocation of resources without limits
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mark3labs mcp-go | v ≤ 1.2.1 | — |
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