CVE-2021-21374

moderate-risk
Published 2021-03-26

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 without full verification of the SSL/TLS certificate due to the default setting of httpClient. 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.

Do I need to act?

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0.31% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
8
CVSS 8.1/10 High
NETWORK / HIGH complexity

Affected Products (1)

Nim

Affected Vendors

Nim-Lang

References (8)

Exploit https://consensys.net/diligence/vulnerabilities/nim-insecure-ssl-tls-defaults-re...
Patch https://github.com/nim-lang/Nim/pull/16940
Release Notes https://github.com/nim-lang/nimble/blob/master/changelog.markdown#0130
Third Party Advisory https://github.com/nim-lang/security/security/advisories/GHSA-c2wm-v66h-xhxx
Exploit https://consensys.net/diligence/vulnerabilities/nim-insecure-ssl-tls-defaults-re...
Patch https://github.com/nim-lang/Nim/pull/16940
Release Notes https://github.com/nim-lang/nimble/blob/master/changelog.markdown#0130
Third Party Advisory https://github.com/nim-lang/security/security/advisories/GHSA-c2wm-v66h-xhxx
30
/ 100
moderate-risk
Severity 24/34 · High
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal