CVE-2023-43645

Denial of service from circular relationship definitions in OpenFGA

MEDIUM
5.9
CVSS Score
Published: September 26, 2023 at 08:58 PM UTC
Updated: June 17, 2026 at 06:26 AM UTC
1 product affected across 1 vendorOpenfga

Using openfga by openfga?

Get instant alerts when new vulnerabilities affect openfga - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM5.9
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

Description

OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.3.2
Affected range stops below 1.3.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-835

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card