How severe is CVE-2020-15694?

CVE-2020-15694 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2020-15694 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15694?

CVE-2020-15694 affects Nim-lang Nim. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-15694?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-15694 published?

CVE-2020-15694 was published on 2020-08-14 and last updated on 2026-06-17.

CVE-2020-15694

CVE-2020-15694 is a high-severity vulnerability in Nim-lang Nim with a CVSS 3.x base score of 7.5. 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Nim-lang Nim
Published: 2020-08-14
Last modified: 2026-06-17

Description

In Nim 1.2.4, the standard library httpClient fails to properly validate the server response. For example, httpClient.get().contentLength() does not raise any error if a malicious server provides a negative Content-Length.

Frequently asked questions

What is CVE-2020-15694?: In Nim 1.2.4, the standard library httpClient fails to properly validate the server response. For example, httpClient.get().contentLength() does not raise any error if a malicious server provides a negative Content-Length.
How severe is CVE-2020-15694?: CVE-2020-15694 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2020-15694 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15694?: CVE-2020-15694 affects Nim-lang Nim. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-15694?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-15694 published?: CVE-2020-15694 was published on 2020-08-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:*

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