CVE-2026-55866
Received Received - Intake

Incorrect Permission Cache Poisoning in SpiceDB

Publication date: 2026-09-14

Last updated on: 2026-09-14

Assigner: GitHub, Inc.

Description
SpiceDB is an open source database system for creating and managing security-critical application permissions. From 1.34.0 until 1.54.0, SpiceDB can return PERMISSIONSHIP_HAS_PERMISSION instead of PERMISSIONSHIP_CONDITIONAL_PERMISSION or PERMISSIONSHIP_NO_PERMISSION because checkRequestToKey() and checkRequestToKeyWithCanonical() in internal/dispatch/keys/computed.go omit CheckHints when constructing dispatch Check cache keys. The incorrect result requires a permission combining relations with intersection or exclusion, a subject reachable through caveated and non-caveated branches, LookupResources with a context parameter running concurrently with CheckPermission or CheckBulkPermissions for the same resource and subject, and an enabled dispatch result cache. Under these conditions, a result computed for one hint set can poison the cache entry used by a semantically different authorization check, allowing permission without satisfying the caveat. This issue is fixed in version 1.54.0.

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Meta Information

Published
2026-09-14
Last Modified
2026-09-14
Generated
2026-09-14
AI Q&A
2026-09-14
EPSS Evaluated
N/A
NVD
CVE-2026-55866
EUVD
EUVD-2026-77689

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
spicedb spicedb From 1.34.0 (inc) to 1.54.0 (inc)
spicedb spicedb 1.54.0
authzed spicedb From 1.34.0 (inc) to 1.54.0 (exc)
authzed spicedb 1.54.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

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Executive Summary

This vulnerability in SpiceDB (versions 1.34.0 to 1.54.0) involves cache poisoning due to incorrect cache key generation in dispatch operations. The functions checkRequestToKey() and checkRequestToKeyWithCanonical() fail to include CheckHints when creating cache keys, causing semantically different authorization checks to share the same cache entry. This can lead to incorrect permission responses where PERMISSIONSHIP_HAS_PERMISSION is returned instead of the correct conditional or no permission status.

Detection Guidance

Detecting this vulnerability requires checking if your SpiceDB version is between 1.34.0 and 1.54.0. Run: spicedb version. If the version falls in this range, the system is vulnerable. Additionally, review schema permissions involving caveats and intersections to identify potential misconfigurations.

Impact Analysis

This vulnerability could allow an attacker to bypass intended permission restrictions by manipulating cache entries. If exploited under specific conditions (concurrent requests, caveated permissions, and enabled cache), the system may grant unauthorized access to resources. The impact is limited to scenarios involving complex permission schemas with intersections or exclusions.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by allowing incorrect authorization decisions due to cache poisoning. If an attacker exploits this flaw, they might gain unauthorized access to sensitive data or permissions, violating data protection requirements under these regulations.

Mitigation Strategies

Upgrade SpiceDB to version 1.54.0 or later immediately. If upgrading is not possible, disable the dispatch result cache as a temporary workaround. Monitor authorization responses for incorrect permissions during concurrent operations.

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