Bug 2413926 (CVE-2025-64529)

Summary: CVE-2025-64529 spicedb: SpiceDB: Silent WriteRelationships failure leads to incorrect permissions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: caswilli, kaycoth
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A vulnerability has been identified in the WriteRelationships API of SpiceDB, where large relationship-update requests can be silently dropped when the payload exceeds what the underlying datastore permits. This occurs because the server does not always return an error when processing oversized write operations, especially in schemas that use the exclusion operator and in deployments configured with very high per-call write limits. An attacker or misconfigured client could exploit this behavior by sending an excessively large update request, causing the intended relationship changes to be ignored and resulting in incomplete or inconsistent authorization state.
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Description OSIDB Bzimport 2025-11-10 23:01:58 UTC 
SpiceDB is an open source database system for creating and managing security-critical application permissions. In versions prior to 1.45.2, users who use the exclusion operator somewhere in their authorization schema; have configured their SpiceDB server such that `--write-relationships-max-updates-per-call` is bigger than 6500; and issue calls to WriteRelationships with a large enough number of updates that cause the payload to be bigger than what their datastore allows; will receive a successful response from their `WriteRelationships` call, when in reality that call failed, and receive incorrect permission check results, if those relationships had to be read to resolve the relation involving the exclusion. Version 1.45.2 contains a patch for the issue. As a workaround, set `--write-relationships-max-updates-per-call` to `1000`.