Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The mcp-core Maven package (io.modelcontextprotocol.sdk) is vulnerable to DNS rebinding in versions before 1.0.0 because it did not validate the Origin header. An attacker who lures a developer to a malicious website can use the victim's browser to make tool calls to a local or private-network MCP server. Upgrade to version 1.0.0 or later. Alternatively, place the server behind a reverse proxy that strictly validates the Host and Origin headers.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.6 | High | 4.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0016, the 5th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:17 UTC First seen by agentprime
- 31 Oct 2026, 14:17 UTC Confirmed by OSV