Bug 2562272 (CVE-2026-77167)

Summary: CVE-2026-77167 nextcloud: Nextcloud: Denial of Service via federated share endpoint abuse
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Nextcloud. An unauthenticated remote attacker can abuse the federated sharing endpoint to inject arbitrary rows into the database. Because these entries are never automatically cleaned up, they cause persistent Denial of Service (DoS) conditions that disrupt system availability.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2569421, 2569422    
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Description OSIDB Bzimport 2026-10-27 18:24:26 UTC 
Abusing the federated share endpoint, an attacker can write arbitrary rows into the oc_share_external database table. These rows persist indefinitely — there is no automatic cleanup mechanism. Three distinct denial-of-service conditions follow from this write primitive, all triggered from the same unauthenticated source and all self-renewing on a 24-hour cycle for as long as the injected rows remain in the database.