CVE-2026-34221 json
MikroORM has Prototype Pollution in Utils.merge
published 2026-03-29 7 mo ago modified 2026-07-24 3 mo ago also GHSA-qpfv-44f3-qqx6 , EUVD-2026-17488
- cvss
- 9.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 32%
- public exploits
- 0
- none known
Summary
MikroORM is a TypeScript ORM for Node.js based on Data Mapper, Unit of Work and Identity Map patterns. Prior to versions 6.6.10 and 7.0.6, a prototype pollution vulnerability exists in the Utils.merge helper used internally by MikroORM when merging object structures. The function did not prevent special keys such as __proto__, constructor, or prototype, allowing attacker-controlled input to modify the JavaScript object prototype when merged. This issue has been patched in versions 6.6.10 and 7.0.6.
Patch / fix
- npm @mikro-orm/core 6.6.10, 7.0.6
- mikro-orm mikroorm 6.6.10, 7.0.6
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:L/SA:L |
| CNA | 4.0 | 8.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @mikro-orm/core | <6.6.10 >=7.0.0-dev.0, <7.0.6 |
6.6.10 7.0.6 |
Affected products
- mikro-orm mikro-orm
Classification
- Weakness
-
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes
References
-
github.com
/mikro-orm/mikro-orm/security/advisories/GHSA-qpfv-44f3-qqx6
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-34221
advisory
-
github.com
/mikro-orm/mikro-orm
package
Sources
- CVE List CVE-2026-34221
- GitHub Advisory GHSA-qpfv-44f3-qqx6
- NVD CVE-2026-34221
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.