What is the CVSS score of CVE-2025-65099?

CVE-2025-65099 has a CVSS 4.0 base score of 7.7 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. EPSS exploitation probability: 0.2%.

How to fix or mitigate CVE-2025-65099?

Within 30 days: Identify all affected systems running a project via yarn plugins and apply vendor patches as part of regular patch cycle. Validate that input sanitization is in place for all user-controlled parameters.

Claude Code CVE-2025-65099

HIGH

Code Injection (CWE-94)

2025-11-19 security-advisories@github.com

RCE Code Injection Claude Code Anthropic

7.7

CVSS 4.0 · Vendor: github

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Vulnerability Assessment

Weakness	CWE CWE-94 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Code injection prevention, sandbox exec MITRE ATT&CK 2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 7.7 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. EPSS exploitation probability: 0.15%.
Exploit ScenarioDerived	A remote attacker could inject and execute arbitrary code within the application by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Claude Code is an agentic coding tool. Rated high severity (CVSS 7.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Never evaluate user-controlled input as code. Use sandboxing, disable dangerous functions, apply strict input validation.

Affected Packages

npm @anthropic-ai/claude-code fix: 1.0.39

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in npm

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Code Injection (CWE-94), which allows attackers to inject and execute arbitrary code within the application. Claude Code is an agentic coding tool. Prior to version 1.0.39, when running on a machine with Yarn 3.0 or above, Claude Code could have been tricked to execute code contained in a project via yarn plugins before the user accepted the startup trust dialog. Exploiting this would have required a user to start Claude Code in an untrusted directory and to be using Yarn 3.0 or above. This issue has been patched in version 1.0.39. Affected products include: Anthropic Claude Code. Version information: version 1.0.39.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (github) PRIMARY 7.7 HIGH

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (github) · only source for this CVE.

CVSS VectorVendor: github

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

Present

Privileges Required

None

User Interaction

Passive

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

High

Vulnerable system: Availability

High

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

CVE Published

Nov 19, 2025 - 18:15 nvd

HIGH 7.7

DescriptionCVE.org

Claude Code is an agentic coding tool. Prior to version 1.0.39, when running on a machine with Yarn 3.0 or above, Claude Code could have been tricked to execute code contained in a project via yarn plugins before the user accepted the startup trust dialog. Exploiting this would have required a user to start Claude Code in an untrusted directory and to be using Yarn 3.0 or above. This issue has been patched in version 1.0.39.

Executive ViewAI

Why It Matters

Organizations using a project via yarn plugins face notable risk from CVE-2025-65099, a code injection vulnerability rated CVSS 7.7. Successful exploitation could allow attackers to execute arbitrary code or commands on affected systems, potentially leading to full system compromise. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Deploy WAF rules to block injection patterns; (2) Restrict network access to affected components; (3) Enable enhanced logging for suspicious activity.

Threat Intelligence Overview

EPSS Score

0.2%

Top 64% exploitable

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.2%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +38

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.