CVE-2026-86063 with a CVSS score of 7.5 is a plugin hash pin bypass in the plugin installation flow of Claude Code and Claude Desktop, affecting the @anthropic-ai/claude-code npm package. The vulnerability occurs because the installer checked out a marketplace's pinned commit SHA using git checkout without verifying that the resulting HEAD matched the pinned SHA. An attacker who controls a plugin's upstream repository can create a branch named identically to the pinned 40-character SHA, causing the checkout to silently resolve to the attacker's branch tip instead of the reviewed commit. This allows attacker-controlled code to be installed while bypassing the pinned hash. Exploitation requires a user to install a malicious plugin, pin to a safe hash, and use a plugin source hosted on a Git platform that permits SHA-shaped branch names. The business impact is that organizations relying on plugin hash pinning for supply-chain integrity may receive unreviewed code, increasing the risk of malicious code execution, data compromise, credential theft, and disruption of development workflows.
The following reports contain further technical details:[/subscribe_to_unlock_form]
CVE-2026-86063 with a CVSS score of 7.5 is a plugin hash pin bypass in the plugin installation flow of Claude Code and Claude Desktop, affecting the @anthropic-ai/claude-code npm package. The vulnerability occurs because the installer checked out a marketplace's pinned commit SHA using git checkout without verifying that the resulting HEAD matched the pinned SHA. An attacker who controls a plugin's upstream repository can create a branch named identically to the pinned 40-character SHA, causing the checkout to silently resolve to the attacker's branch tip instead of the reviewed commit. This allows attacker-controlled code to be installed while bypassing the pinned hash. Exploitation requires a user to install a malicious plugin, pin to a safe hash, and use a plugin source hosted on a Git platform that permits SHA-shaped branch names. The business impact is that organizations relying on plugin hash pinning for supply-chain integrity may receive unreviewed code, increasing the risk of malicious code execution, data compromise, credential theft, and disruption of development workflows.
The following reports contain further technical details:[emaillocker id="1283"]
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