Official MCP Python SDK Flaw Can Let Malicious Servers Steal OAuth Credentials
A malicious MCP server could trick an application built on the official MCP Python SDK into handing over the OAuth credentials it uses to log in to a real service, the SDK's maintainers said in a security advisory. Affected versions sent the client secret, the authorization code, and the PKCE proof key to a token endpoint the attacker controlled. The fix is in versions 1.30.0 and
What happened
A malicious MCP server could trick an application built on the official MCP Python SDK into handing over the OAuth credentials it uses to log in to a real service, the SDK's maintainers said in a security advisory. Affected versions sent the client secret, the authorization code, and the PKCE proof key to a token endpoint the attacker controlled. The fix is in versions 1.30.0 and
Why it matters
The development may change operating conditions or market expectations around Security. Further confirmation and measurable outcomes matter.
Affected entities
View evidence
1 reports · 1 original report · 1 independent
- The Hacker NewsPrimary source · Supports · EN · 100%Official MCP Python SDK Flaw Can Let Malicious Servers Steal OAuth Credentials ↗
Claims
- Official MCP Python SDK Flaw Can Let Malicious Servers Steal OAuth Credentials Observed
Conflicts
No material conflict detected in the available evidence.
Timeline
- First reported
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