Token Cache Reuse in mcp-toolbox-sdk-python
cve-program · CVE-2026-19202
PublishedA caching flaw in the toolbox-core package of the mcp-toolbox-sdk-python SDK causes the same Google ID token to be cached and reused across different audiences. If an application uses the SDK to authenticate to two or more different audiences within the same process, the module-level token cache fails to key its cached tokens by the requested audience. Consequently, a valid, unexpired token minted for a sensitive service (Service A) can be retrieved from the cache and sent to a secondary service (Service B). An attacker who operates, compromises, or monitors traffic to Service B can capture this token and replay it to impersonate the victim application against Service A.
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cve-program · CVE-2026-19202
PublishedToken Cache Reuse in mcp-toolbox-sdk-python
A caching flaw in the toolbox-core package of the mcp-toolbox-sdk-python SDK causes the same Google ID token to be cached and reused across different audiences. If an application uses the SDK to authenticate to two or more different audiences within the same process, the module-level token cache fails to key its cached tokens by the requested audience. Consequently, a valid, unexpired token minted for a sensitive service (Service A) can be retrieved from the cache and sent to a secondary service (Service B). An attacker who operates, compromises, or monitors traffic to Service B can capture this token and replay it to impersonate the victim application against Service A.
- Source published
- 22 Sep 2026 21:48:26 UTC
- Source modified
- 23 Sep 2026 15:01:51 UTC
- Saved here
- 23 Oct 2026 15:48:27 UTC
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CVSS 4.0 · 9.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N