CVE-2020-7770
Prototype Pollution
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Prototype Pollution
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
- Record
CVE-2020-7770- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - Updated
- 2026-11-02
EUVDEUVD-2021-0999
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
- Record
EUVD-2021-0999- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-7h43-gx24-p529
Prototype pollution in json8
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
- Record
GHSA-7h43-gx24-p529- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-1321
- Updated
- 2026-11-02
NVD
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
- Record
CVE-2020-7770- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSV
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
- Record
CVE-2020-7770- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-7h43-gx24-p529
Prototype pollution in json8
This affects the package json8 before 1.0.3. The function adds in the target object the property specified in the path, however it does not properly check the key being set, leading to a prototype pollution.
- Record
GHSA-7h43-gx24-p529- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-1321
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
json8npm |
before 1.0.3 | 1.0.3 |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-7770 is a medium vulnerability (CVSS 6.5) in Json8 Project Json8, published November 12, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.89%, the 79th percentile. Fixed in json8 1.0.3.