CVE-2021-21372 | Nimble arbitrary code execution for specially crafted package metadata

Exp

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.

Published: 2021-03-26 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-21372 is rated High Exploit Risk (77.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.79%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-21372

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-21372

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-03 1.25% 1.79% +0.54%
2 2025-11-21 1.49% 1.25% -0.25%
3 2025-11-18 — 1.49% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21372

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.3 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 6.0 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-21372

OS Trackers for CVE-2021-21372

vendor priority summary link
debian not yet assigned CVE-2021-21372 not yet assigned priority: Debian including 1 source packages (nim), 4 status rows across 4 suites (bookworm, bullseye, forky, sid): resolved 4. https://security-tracker.debian.org/tracker/CVE-2021-21372
ubuntu medium CVE-2021-21372 medium priority: Ubuntu including 1 source packages (nim), 14 status rows across 14 suites (bionic, focal, groovy, hirsute, impish, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 7, needs-triage 6, DNE 1. https://ubuntu.com/security/CVE-2021-21372

Affected software / configurations for CVE-2021-21372

Vendor Product Version Raw CPE
nim-lang nim < 1.2.10 cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:*
nim-lang nim >= 1.4.0, < 1.4.4 cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:*

References for CVE-2021-21372

cvelogic Threat Intelligence