claude-code: Missing Origin Validation in WebSockets
CVE-2025-52882 is a high-severity missing origin validation in websockets vulnerability in claude-code from Anthropics, with a CVSS 4.0 base score of 8.8 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: >= 0.2.116 < 1.0.24. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.36% 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 | >= 0.2.116 < 1.0.24 | 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
- PassiveA user only needs to do something routine, such as viewing a page.
- 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)
- NoneNo loss of availability on the vulnerable system.
- Confidentiality (other systems)
- HighSerious loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- HighSerious 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:P/VC:H/VI:H/VA:N/SC:H/SI:H/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. Claude Code extensions in VSCode and forks (e.g., Cursor, Windsurf, and VSCodium) and JetBrains IDEs (e.g., IntelliJ, Pycharm, and Android Studio) are vulnerable to unauthorized websocket connections from an attacker when visiting attacker-controlled webpages. Claude Code for VSCode IDE extensions versions 0.2.116 through 1.0.23 are vulnerable. For Jetbrains IDE plugins, Claude Code [beta] versions 0.1.1 through 0.1.8 are vulnerable. In VSCode (and forks), exploitation would allow an attacker to read arbitrary files, see the list of files open in the IDE, get selection and diagnostics events from the IDE, or execute code in limited situations where a user has an open Jupyter Notebook and accepts a malicious prompt. In JetBrains IDEs, an attacker could get selection events, a list of open files, and a list of syntax errors. Claude released a patch for this issue on June 13th, 2025. Although Claude Code auto-updates when a user launch it and auto-updates the extensions, users should take the following steps, though the exact steps depend on one's integrated development environment (IDE). For VSCode, Cursor, Windsurf, VSCodium, and other VSCode forks, check the extension Claude Code for VSCode. Open the list of Extensions (View->Extensions), look for Claude Code for VSCode among installed extensions, update or uninstall any version prior to 1.0.24, and restart the IDE. For JetBrains IDEs including IntelliJ, PyCharm, and Android Studio, check the plugin Claude Code [Beta]. Open the Plugins list, look for Claude Code [Beta] among installed extensions, update or uninstall any version prior to 0.1.9, and restart the IDE.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Origin Validation in WebSockets
The product uses a WebSocket, but it does not properly verify that the source of data or communication is valid.
How developers prevent this class of flaw
- Enable CORS-like access restrictions by verifying the 'Origin' header during the WebSocket handshake.
- Use a randomized CSRF token to verify requests.
- Use TLS to securely communicate using 'wss' (WebSocket Secure) instead of 'ws'.
More Missing Origin Validation in WebSockets vulnerabilities (CWE-1385)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in claude-code
- 7.7 High severity
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 9.1 Critical severity
- 7.8 High severity
Recent Missing Origin Validation in WebSockets vulnerabilities
- 8.8 High severity
- 9.4 Critical severity
- 9.8 Critical severity
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