Security Digest · Vulnerability record
CVE-2026-86063: Claude Code: Plugin Hash Pin Bypass Allows Bypass of Hash Pinning
Claude Code is an agentic coding tool. Prior to 2.1.179, the Claude Code and Claude Desktop plugin installation flow runs git checkout for a marketplace-pinned commit without verifying that the resulting HEAD equals the pinned 40-character SHA.
CVSS 7.5 High EPSS 0.2% · p6 Check exposure
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.2%, percentile 6: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 6% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Editorial verdict: Check exposure. Plugin4Shell: Plugin Pin Bypass in AI Coding Agents — Claude Code and Codex users on current versions are fixed; the real exposure is Copilot or Gemini CLI plugins that auto-update from repositories hosted outside GitHub.
What it is
Claude Code is an agentic coding tool. Prior to 2.1.179, the Claude Code and Claude Desktop plugin installation flow runs git checkout for a marketplace-pinned commit without verifying that the resulting HEAD equals the pinned 40-character SHA. An attacker who controls a plugin repository on a Git host that permits SHA-shaped branch names can create a branch named after the reviewed commit, causing checkout to select the branch tip and install attacker-controlled plugin code. Exploitation requires a user to install the malicious plugin and pin it to the ostensibly safe hash. This issue is fixed in version 2.1.179.
Weakness type: CWE-494, CWE-829.
Product: anthropics claude-code · Assigned by: GitHub_M · Published: 2026-10-13
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| anthropics | claude-code | < 2.1.179 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 7.5 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: present (depends on deployment conditions)
- Privileges required: none (no login)
- User interaction: active
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.17% probability of exploitation activity in the next 30 days; percentile 6.
Timeline
- — erroneo.us brief: Plugin4Shell: Plugin Pin Bypass in AI Coding Agents
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- CVE.org record CVE-2026-86063 cve.org
- NVD entry CVE-2026-86063 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com