How severe is CVE-2020-7637?

CVE-2020-7637 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2020-7637 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-7637?

CVE-2020-7637 affects Class-transformer Project Class-transformer. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-7637?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-7637 published?

CVE-2020-7637 was published on 2020-04-06 and last updated on 2026-06-17.

CVE-2020-7637

CVE-2020-7637 is a medium-severity vulnerability in Class-transformer Project Class-transformer with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1321.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1321
Affected product: Class-transformer Project Class-transformer
Published: 2020-04-06
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-7637?: 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.
How severe is CVE-2020-7637?: CVE-2020-7637 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2020-7637 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-7637?: CVE-2020-7637 affects Class-transformer Project Class-transformer. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-7637?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-7637 published?: CVE-2020-7637 was published on 2020-04-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:class-transformer_project:class-transformer:*:*:*:*:*:node.js:*:*

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