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CVE-2020-15694In Nim 1.2.4, the standard library httpClient fails to properly validate the server response. For example,…
- 7.5HighCVSS base score
- 2.3%Exploitation in 30 daysEPSS · top 16% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mitre
- 32 days later
· 32 days later
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 2.3% · top 16% of all CVEs (12 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
n/a
- affected n/a
References
References4
- https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241 (opens in a new tab)x_refsource_MISCx_transferred
- https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html (opens in a new tab)x_refsource_CONFIRMx_transferred
- [oss-security] 20210204 [CVE-2020-15693, CVE-2020-15694] Nim - stdlib Httpclient - Header Crlf Injection & Server Response Validation (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://consensys.net/diligence/vulnerabilities/nim-httpclient-header-crlf-injection/ (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2020-7681 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2020-15694)Record last updated .