CVE-2018-3722
Prototype Pollution in merge-deep
merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via proto, causing the addition or modification of an existing property that will exist on all objects.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via proto, causing the addition or modification of an existing property that will exist on all objects.
- Record
CVE-2018-3722- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.5 Medium
AV:N/AC:L/Au:S/C:P/I:P/A:P - Weakness
- CWE-471
- Updated
- 2026-11-02
CVE List No score
merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via proto, causing the addition or modification of an existing property that will exist on all objects.
- Record
CVE-2018-3722- Weakness
- CWE-471
- Updated
- 2026-11-02
EUVDEUVD-2018-0254 No score
merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via proto, causing the addition or modification of an existing property that will exist on all objects.
- Record
EUVD-2018-0254- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-9g9w-hmvj-5h57
Prototype Pollution in merge-deep
Versions of merge-deep before 3.0.1 are vulnerable to prototype pollution via merging functions.
Recommendation
Update to version 3.0.1 or later.
- Record
GHSA-9g9w-hmvj-5h57- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-471
- Updated
- 2026-11-02
OSV
merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via proto, causing the addition or modification of an existing property that will exist on all objects.
- Record
CVE-2018-3722- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-9g9w-hmvj-5h57
Prototype Pollution in merge-deep
Versions of merge-deep before 3.0.1 are vulnerable to prototype pollution via merging functions.
Recommendation
Update to version 3.0.1 or later.
- Record
GHSA-9g9w-hmvj-5h57- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-471
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
merge-deepnpm |
before 3.0.1 | 3.0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-3722 is a high vulnerability (CVSS 8.8) in Hackerone Merge-deep Node Module, published June 7, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.00%, the 80th percentile. Fixed in merge-deep 3.0.1.