What’s Vulnerable › Vulnerabilities

CVE-2020-15693

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-08-14 · updated 2026-06-17
• Weakness: CWE-74

Description

In Nim 1.2.4, the standard library httpClient is vulnerable to a CR-LF injection in the target URL. An injection is possible if the attacker controls any part of the URL provided in a call (such as httpClient.get or httpClient.post), the User-Agent header value, or custom HTTP header names or values.

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#L1023
• 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#L1023
• https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html

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