Vulnerability · Published Mar 26, 2026 · Assigned by GitHub_M
CVE-2026-33620PinchTab: API Bearer Token Exposed in URL Query Parameter via Server Logs and Intermediary Systems
Medium 4.3
In plain English
A medium-severity security flaw in pinchtab from pinchtab. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. PinchTab `v0.7.8` through `v0.8.3` accepted the API token from a `token` URL query parameter in addition to the `Authorization` header. When a valid API credential is sent in the URL, it can be exposed through request URIs recorded by intermediaries or client-side tooling, such as reverse proxy access logs, browser history, shell history, clipboard history, and tracing systems that capture full URLs. This issue is an unsafe credential transport pattern rather than a direct authentication bypass. It only affects deployments where a token is configured and a client actually uses the query-parameter form. PinchTab's security guidance already recommended `Authorization: Bearer <token>`, but `v0.8.3` still accepted `?token=` and included first-party flows that generated and consumed URLs containing the token. This was addressed in v0.8.4 by removing query-string token authentication and requiring safer header- or session-based authentication flows.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/pinchtab/pinchtab | 0.8.4 | GHSA-mrqc-3276-74f8 |
| Go | github.com/pinchtab/pinchtab | 0.8.4 | GO-2026-4822 |
Affected products (as reported)
Weakness: CWE-598 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
References
- https://github.com/pinchtab/pinchtab/security/advisories/GHSA-mrqc-3276-74f8 x_refsource_CONFIRM
- https://github.com/pinchtab/pinchtab/releases/tag/v0.8.4 x_refsource_MISC