CVE-2026-55640
Unauthenticated webhook allows deletion/re-indexing of Nextcloud MCP vector embeddings.
Is CVE-2026-55640 being exploited?
Not confirmed. CVE-2026-55640 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.48% probability of exploitation in the next 30 days.
How severe is CVE-2026-55640?
CVE-2026-55640 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-55640?
Yes. A fix has been recorded for CVE-2026-55640. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-55640 affect?
CVE-2026-55640 affects Nextcloud MCP Server <0.117.2, POST /webhooks/nextcloud endpoint, Qdrant vector index backend. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-55640?
Upgrade to 0.117.2; set WEBHOOK_SECRET and restrict access to the webhook endpoint.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated requests can delete or trigger re-indexing of any user's vector embeddings and destroy the Qdrant semantic search index.
Immediate action required
- affected< 0.117.2
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.