{"id":"CVE-2020-15694","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-15694","generatedAt":"2026-10-27T22:25:35.870Z","title":"For example, httpClient.get().contentLength() does not raise any error if a malicious server provides a negative Content-Length.","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.","published":"2020-08-14T19:15:13.000Z","lastModified":"2026-06-17T02:57:04.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"cwe":["CWE-20"],"affected":["nim-lang/nim"],"epss":{"score":0.02331,"percentile":0.83425,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (2.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"http://www.openwall.com/lists/oss-security/2021/02/04/2","tags":["Exploit","Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://consensys.net/diligence/vulnerabilities/nim-httpclient-header-crlf-injection/","tags":["Exploit","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html","tags":["Release Notes","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/02/04/2","tags":["Exploit","Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://consensys.net/diligence/vulnerabilities/nim-httpclient-header-crlf-injection/","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html","tags":["Release Notes","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-15694","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}