Widely used database server; unauthenticated DoS could disrupt many orgs; critical infrastructure impact.
CVE-2026-9740
Unauthenticated crash of mongod via crafted BSON data.
Is CVE-2026-9740 being exploited?
Not confirmed. CVE-2026-9740 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 0.34% probability of exploitation in the next 30 days.
How severe is CVE-2026-9740?
CVE-2026-9740 is rated High with a CVSS score of 8.7. 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-2026-9740?
Yes. A fix has been recorded for CVE-2026-9740. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-9740 affect?
CVE-2026-9740 affects MongoDB Server. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-9740?
Patch when available; restrict access to DB servers; monitor mongod crashes.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote crash/DoS of MongoDB server by recursive BSON validation, risking service disruption.
Immediate action required
- affected>= 8.3.0 and < 8.3.3
- affected>= 8.2.0 and < 8.2.10
- affected>= 8.0.0 and < 8.0.24
- affected>= 7.0.0 and < 7.0.35
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.