# CVE-2020-15694: nim: In Nim 1.2.4, the standard library httpClient fails to properly validatethe server response

CVE-2020-15694 is fixed in nim on 1 platform, first by nim 1.2.6-1, released January 16, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2020-15694
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0233
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no

## Description

In Nim 1.2.4, the standard library httpClient fails to properly validatethe server response. For example, httpClient.get().contentLength() does notraise any error if a malicious server provides a negative Content-Length.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nim Ubuntu 24.10 (oracular) | 1.2.6-1 | [nim 1.2.6-1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-nim-1.2.6-1.md) | Jan 16, 2026 |
| Linux | nim Ubuntu 25.04 (plucky) | 1.2.6-1 | [nim 1.2.6-1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-nim-1.2.6-1.md) | Jan 16, 2026 |

---

Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.