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TI-2021-04471 Aliases CVE-2021-21372

Nimble arbitrary code execution for specially crafted package metadata

Priority MEDIUM 44CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-78.

Summary

Nimble is a package manager for the Nim programming language. In Nim release version before versions 1.2.10 and 1.4.4, Nimble doCmd is used in different places and can be leveraged to execute arbitrary commands. An attacker can craft a malicious entry in the packages.json package list to trigger code execution.

Why it matters now

EPSS 0.03618 89th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed security (nim-lang): 1.2.10, 1.4.4

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
nim-langsecuritybefore 1.2.10; 1.4.0 to before 1.4.41.2.10, 1.4.4Patch availableCNA
  • security Vendornim-lang Affected before 1.2.10; 1.4.0 to before 1.4.4 Fixed in 1.2.10, 1.4.4 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:*before 1.2.10; 1.4.0 to before 1.4.4Vulnerablenim-lang
  • cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:* Versions before 1.2.10; 1.4.0 to before 1.4.4 Vulnerable ·nim-lang

Remediation

  • Fix · CNA security (nim-lang) Fixed in 1.2.10, 1.4.4

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-21372

References

Exploit 1

Patch 1

Advisory 2

  • TI-2020-12364 In Nim 1.2.4, the standard library browsers mishandles the URL argument to… CVSS 3.1CRITICAL 9.8
  • TI-2020-12363 In Nim before 1.2.6, the standard library asyncftpclient lacks a check for whether a… CVSS 3.1CRITICAL 9.8
  • TI-2021-04473 Nimble fails to validate certificates due to insecure httpClient defaults CVSS 3.1HIGH 8.1
  • TI-2020-12366 In Nim 1.2.4, the standard library httpClient fails to properly validate the server… CVSS 3.1HIGH 7.5
  • TI-2021-04472 Nimble falls back to insecure http url when fetching packages CVSS 3.1HIGH 7.5
  • TI-2021-10206 Nim stdlib httpClient does not validate peer certificates by default CVSS 3.1HIGH 7.5
See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences