VulnerabilityPublished 13 Aug 2026Updated 3 Nov 2026

CVE-2026-23890: Pnpm@9 · pnpm scoped bin name Path Traversal allows arbitrary file creation outside node_modules/.bin

Affects pnpm@9Source GCVE Database

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Not known to be exploited · CVSS 6.5 Medium.

Data as of 4 Nov 2026, 01:45 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Homebrewpnpm@9`pkg:brew/pnpm%409`Other threats	Affected >=9.15.4	Fixed in–

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AI-suggested

Until an official fix is available, users should avoid installing untrusted packages and monitor pnpm vendor communications for updates addressing this vulnerability.

Description

A path traversal vulnerability in pnpm version 9.15.4 and later allows malicious npm packages to create executable shims or symlinks outside the intended node_modules/.bin directory. This occurs because bin names starting with '@' bypass validation and path traversal sequences are preserved after normalization, enabling arbitrary file creation outside the expected directory.

Impact

This vulnerability affects all pnpm users who install npm packages, including CI/CD pipelines using pnpm. It allows attackers to overwrite configuration files, scripts, or other sensitive files outside the node_modules/.bin directory, potentially leading to arbitrary code execution or configuration manipulation. The CVSS score is 6.5 (medium severity) with an impact primarily on integrity.

Summary

The vulnerability in pnpm's bin linking mechanism arises from insufficient validation and normalization of bin names. Bin names beginning with '@' bypass the validation filter, and the normalization function preserves path traversal sequences such as '../../'. The normalized bin name is then used directly in path joining operations without further validation, allowing an attacker to create files or symlinks outside the node_modules/.bin directory. A proof of concept demonstrates creating a .npmrc file in the project root by specifying a bin name with path traversal sequences in a malicious package.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 01:45 UTC

Technical details

References

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