CVE-2026-34221
Prototype pollution in MikroORM Utils.merge.
Is CVE-2026-34221 being exploited?
Not confirmed. CVE-2026-34221 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 0.38% probability of exploitation in the next 30 days.
How severe is CVE-2026-34221?
CVE-2026-34221 is rated High with a CVSS score of 8.3. 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-2026-34221?
Yes. A fix has been recorded for CVE-2026-34221. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-34221 affect?
CVE-2026-34221 affects MikroORM, Node.js apps using MikroORM. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-34221?
Upgrade to MikroORM 6.6.10+ or 7.0.6+
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker-controlled input can modify Object.prototype via Utils.merge, risking property injection and hijacked app behavior.
Patch when possible
- affected< 6.6.10
- affected>= 7.0.0-rc.0 and < 7.0.6
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.