CVE-2021-21373

Nimble falls back to insecure http url when fetching packages

MEDIUM

5.9

CVSS Score

Published: March 26, 2021 at 09:25 PM UTC

Updated: June 17, 2026 at 03:35 AM UTC

2 products affected across 1 vendorNimLang Nim

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Severity

MEDIUM5.9

Exploit prediction

EPSS 1%

Description

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 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nim · Nim Lang

95%

v < 1.2.101.4.0 ≤ v < 1.4.4

Affected range stops below 1.2.10, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.4.4, so it looks safe — our inference, not a vendor statement

Lang Nim · Nim Lang

60%

v < 1.2.10v < 1.4.4

Affected range stops below 1.2.10, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.4.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

x_refsource_MISCExploitThird Party Advisory

Source: [email protected]

https://consensys.net/diligence/vulnerabilities/nim-insecure-ssl-tls-defaults-remote-code-execution/

x_refsource_MISCRelease NotesThird Party Advisory

Source: [email protected]

https://github.com/nim-lang/nimble/blob/master/changelog.markdown#0130

x_refsource_CONFIRMThird Party Advisory

Source: [email protected]

https://github.com/nim-lang/security/security/advisories/GHSA-8w52-r35x-rgp8

CVSS

5.9MEDIUM[email protected]

Attack Vector: NETWORK
Complexity: HIGH
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-348CWE-295

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