CVE-2020-7637
Prototype pollution in class-transformer
class-transformer before 0.3.1 allow attackers to perform Prototype Pollution. The classToPlainFromExist function could be tricked into adding or modifying properties of Object.prototype using a proto payload.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
class-transformer before 0.3.1 allow attackers to perform Prototype Pollution. The classToPlainFromExist function could be tricked into adding or modifying properties of Object.prototype using a proto payload.
- Record
CVE-2020-7637- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-1321
- Updated
- 2026-11-02
CVE List No score
class-transformer before 0.3.1 allow attackers to perform Prototype Pollution. The classToPlainFromExist function could be tricked into adding or modifying properties of Object.prototype using a proto payload.
- Record
CVE-2020-7637- Updated
- 2026-11-02
EUVDEUVD-2020-0368 No score
class-transformer before 0.3.1 allow attackers to perform Prototype Pollution. The classToPlainFromExist function could be tricked into adding or modifying properties of Object.prototype using a proto payload.
- Record
EUVD-2020-0368- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-6gp3-h3jj-prx4
Prototype pollution in class-transformer
class-transformer through 0.2.3 is vulnerable to Prototype Pollution. The 'classToPlainFromExist' function could be tricked into adding or modifying properties of 'Object.prototype' using a 'proto' payload.
- Record
GHSA-6gp3-h3jj-prx4- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-915, CWE-1321
- Updated
- 2026-11-02
OSV
class-transformer before 0.3.1 allow attackers to perform Prototype Pollution. The classToPlainFromExist function could be tricked into adding or modifying properties of Object.prototype using a proto payload.
- Record
CVE-2020-7637- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-6gp3-h3jj-prx4
Prototype pollution in class-transformer
class-transformer through 0.2.3 is vulnerable to Prototype Pollution. The 'classToPlainFromExist' function could be tricked into adding or modifying properties of 'Object.prototype' using a 'proto' payload.
- Record
GHSA-6gp3-h3jj-prx4- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-1321, CWE-915
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
class-transformernpm |
before 0.3.1 | 0.3.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| 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-2020-7637 is a medium vulnerability (CVSS 5.3) in Class-transformer Project Class-transformer, published April 6, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.19%, the 68th percentile. Fixed in class-transformer 0.3.1.
References
github.com/typestack/class-transformer/commit/8f04eb9db02de708f1a20f6f2d2bb309b2fed01e
snyk.io/vuln/SNYK-JS-CLASSTRANSFORMER-564431
nvd.nist.gov/vuln/detail/CVE-2020-7637