CVE-2026-82273: Mastra Memory API Thread Ownership Check Is a No-op When mapUserToResourceId Is Unset

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-28 · updated 2026-09-23
Weakness: CWE-862

Description

Mastra through 1.63.0 contains an authentication bypass vulnerability in the memory API thread ownership validation when mapUserToResourceId callback is omitted from configuration. Authenticated attackers can enumerate all threads via GET /api/memory/threads and read conversation history and metadata of other resource owners.

Affected products

mastra-ai mastra: through 1.63.0

References

https://github.com/mastra-ai/mastra
https://github.com/mastra-ai/mastra/blob/b7e66f0c478a227985e0062794ef058c3714fabf/packages/server/src/server/handlers/utils.ts
https://github.com/mastra-ai/mastra/issues/18911
https://www.vulncheck.com/advisories/mastra-memory-api-thread-ownership-check-is-a-no-op-when-mapusertoresourceid-is-unset
https://github.com/mastra-ai/mastra/issues/18911

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