CVE-2026-77167

High

Description

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.

SeverityHigh
CVSS7.5
Exploit probability—
ProductNextcloud Server
PublishedOct 27, 2026
First seenOct 27, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Nextcloud server22.0.0 ≤ v ≤ 34.0.0—

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