CVE-2026-126658 · AI agents & MCP
NO FIX YET · SEE WHAT TO DO
ByteStash, a self-hosted code snippet manager, does not check whether an account is still active when validating an API key. Someone holding the API key of a deactivated account can keep reading, creating, changing and deleting that account's snippets, and use every MCP tool.
first public Nov 10, 2026 · 1 source
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Teams that run ByteStash themselves and issue API keys to user accounts. Exposure comes from keys that outlive the account they belong to, which then reach the snippet API and the MCP endpoint. Instances that do not issue API keys, or that are on 1.6.2 or later, are not affected.
Not affected if no-api-keys-issued, version-1.6.2-or-later
Who cares api-keys, bytestash, mcp, self-hosted
1.5.10 up to but not including 1.6.2.1.6.2 or later.ByteStash 1.5.10 before 1.6.2 contains an insufficient session expiration vulnerability that allows holders of API keys to keep access after account deactivation because validateApiKey never checks account status. Attackers holding a deactivated account's API key can read, create, modify and delete its snippets via /api/snippets and use every MCP tool via /mcp.
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