What’s Vulnerable › Vulnerabilities

CVE-2020-15694

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-08-14 · updated 2026-06-17
• Weakness: CWE-20

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.

Affected products

• nim-lang Nim: through 1.2.6

References

• http://www.openwall.com/lists/oss-security/2021/02/04/2
• https://consensys.net/diligence/vulnerabilities/nim-httpclient-header-crlf-injection/
• https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241
• https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html
• http://www.openwall.com/lists/oss-security/2021/02/04/2
• https://consensys.net/diligence/vulnerabilities/nim-httpclient-header-crlf-injection/
• https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241
• https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html

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