CVE-2026-86063
Description
A flaw was found in Claude Code. When installing a plugin pinned to a specific commit hash, the application does not verify that the checked-out version matches the expected Secure Hash Algorithm (SHA) identifier. A remote attacker controlling a repository can create a branch named after the reviewed commit hash, tricking the tool into installing attacker-controlled code instead of the approved version. If a user installs the plugin, this issue can lead to arbitrary code execution.
Statement
Red Hat Product Security rates this vulnerability as having an Important severity because successful exploitation enables arbitrary code execution within the developer's environment, while requiring user interaction to install a plugin.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Availability,Confidentiality,Other
Technical Impact: Execute Unauthorized Code or Commands; Alter Execution Logic; Other
An attacker can execute malicious code by compromising the host server, performing DNS spoofing, or modifying the code in transit. Executing untrusted code could compromise the control flow of the program. The untrusted code could execute attacker-controlled commands, read or modify sensitive resources, or prevent the software from functioning correctly for legitimate users.
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