Cyber Resilience

CVE-2021-21373

HighPublic PoC

Published: 26 March 2021

Published
26 March 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:L
EPSS Score 0.0019 40.7th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-21373 is a high-severity Use of Less Trusted Source (CWE-348) vulnerability in Nim-Lang Nim. Its CVSS base score is 7.5 (High).

Operationally, ranked at the 40.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Nimble is a package manager for the Nim programming language. In Nim release versions before versions 1.2.10 and 1.4.4, "nimble refresh" fetches a list of Nimble packages over HTTPS by default. In case of error it falls back to a…

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non-TLS URL http://irclogs.nim-lang.org/packages.json. An attacker able to perform MitM can deliver a modified package list containing malicious software packages. If the packages are installed and used the attack escalates to untrusted code execution.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

nim-lang
nim
≤ 1.2.10 · 1.4.0 — 1.4.4

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-295

When certificates are used to establish component provenance, the control requires correct certificate validation procedures.

addresses: CWE-295

Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.

addresses: CWE-348

Prevents use of less-trusted or adversarial sources by requiring proof of origin and integrity before accepting responses.

addresses: CWE-295

Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.

References