claude-code: Download of Code Without Integrity Check
CVE-2026-86063 is a high-severity download of code without integrity check vulnerability in claude-code from Anthropics, with a CVSS 4.0 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected claude-code versions: < 2.1.179. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of claude-code you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Anthropics | claude-code | < 2.1.179 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- ActiveA user must deliberately do something unusual, such as dismissing a warning.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- HighSerious loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (github.com).
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Download of Code Without Integrity Check
The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.
How developers prevent this class of flaw
- Perform proper forward and reverse DNS lookups to detect DNS spoofing.
- Encrypt the code with a reliable encryption scheme before transmitting.
- Run your code using the lowest privileges that are required to accomplish the necessary tasks. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
More Download of Code Without Integrity Check vulnerabilities (CWE-494)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
References
Patches and release notes
Other vulnerabilities in claude-code
- 7.7 High severity
- 7.5 High severity
- 8.8 High severity
- 9.1 Critical severity
- 7.8 High severity
- 8.8 High severity
Recent Download of Code Without Integrity Check vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
- 7.5 High severity
- 7.7 High severity
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