CVE-2026-42073
published 2026-06-02CVE-2026-42073: OpenClaude is an open-source coding-agent command line interface for cloud and local model providers. Prior to version 0.5.1, the OpenClaude MCP authentication…
PriorityP434medium6.5CVSS 3.1
AVNACLPRNUIRSUCNINAH
EPSS
0.22%
12.2th percentile
OpenClaude is an open-source coding-agent command line interface for cloud and local model providers. Prior to version 0.5.1, the OpenClaude MCP authentication flow starts a temporary local HTTP server to handle OAuth callbacks. To prevent CSRF attacks, the server validates a state parameter against an internally stored value. However, due to a logic flaw in the order of conditionals, an attacker can completely bypass this check and force the server to shut down — without knowing the state value at all. This issue has been patched in version 0.5.1.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| gitlawb | openclaude | < 0.5.1 | 0.5.1 |
| gitlawb | openclaude | >= 0 < 0.5.1 | 0.5.1 |
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VulDB
Gitlawb openclaude up to 0.5.0 state cross-site request forgery (GHSA-c73c-x77g-854r)
vuldb·2026-06-02·CVSS 6.5
CVE-2026-42073 [MEDIUM] Gitlawb openclaude up to 0.5.0 state cross-site request forgery (GHSA-c73c-x77g-854r)
A vulnerability categorized as problematic has been discovered in Gitlawb openclaude up to 0.5.0. The impacted element is an unknown function. Such manipulation of the argument state leads to cross-site request forgery.
This vulnerability is uniquely identified as CVE-2026-42073. The attack can be launched remotely. No exploit exists.
It is advisable to upgrade the affected component.
GHSA
OpenClaude MCP OAuth Callback: State Check Bypass via error Param Leads to DoS
ghsa·2026-05-12
CVE-2026-42073 [MEDIUM] CWE-352 OpenClaude MCP OAuth Callback: State Check Bypass via error Param Leads to DoS
OpenClaude MCP OAuth Callback: State Check Bypass via error Param Leads to DoS
# OAuth State Validation Bypass via `error` Parameter Causes Local Server DoS in MCP Auth Callback
---
## Description
The OpenClaude MCP authentication flow starts a temporary local HTTP server to handle OAuth callbacks. To prevent CSRF attacks, the server validates a `state` parameter against an internally stored value. However, due to a logic flaw in the order of conditionals, an attacker can completely bypass this check and force the server to shut down — without knowing the `state` value at all.
The vulnerable code looks like this:
```typescript
if (!error && state !== oauthState) {
rejectOnce(new Error('OAuth state mismatch - possible CSRF attack'))
return
}
if (error) {
cleanup()
rejectOnce(new Error
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-06-02
Published