CVE-2026-33619 PinchTab has Unauthenticated Blind SSRF in Task Scheduler via Unvalidated callbackUrl

Medium 4.1 Published 26 Mar 2026 Updated 30 Mar 2026

Attackers can exploit unvalidated callback URLs in the optional scheduler to perform blind SSRF, potentially accessing internal network resources.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-33619?

CVE-2026-33619 is a medium-severity server-side request forgery vulnerability in pinchtab, published on 26 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. PinchTab v0.8.3 contains a server-side request forgery issue in the optional scheduler's webhook delivery path. When a task is submitted to `POST /tasks` with a user-controlled `callbackUrl`, the v0.8.3 scheduler sends an outbound HTTP `POST` to that URL when the task reaches a terminal state. In that release, the webhook path validated only the URL scheme and did not reject loopback, private, link-local, or other non-public destinations. Because the v0.8.3 implementation also used the default HTTP client behavior, redirects were followed and the destination was not pinned to validated IPs. This allowed blind SSRF from the PinchTab server to attacker-chosen HTTP(S) targets reachable from the server. This issue is narrower than a general unauthenticated internet-facing SSRF. The scheduler is optional and off by default, and in token-protected deployments the attacker must already be able to submit tasks using the server's master API token. In PinchTab's intended deployment model, that token represents administrative control rather than a low-privilege role. Tokenless deployments lower the barrier further, but that is a separate insecure configuration state rather than impact created by the webhook bug itself. PinchTab's default deployment model is local-first and user-controlled, with loopback bind and token-based access in the recommended setup. That lowers practical risk in default use, even though it does not remove the underlying webhook issue when the scheduler is enabled and reachable. This was addressed in v0.8.4 by validating callback targets before dispatch, rejecting non-public IP ranges, pinning delivery to validated IPs, disabling redirect following, and validating `callbackUrl` during task submission.

Weakness: CWE-918

Which versions are affected by CVE-2026-33619?

3 open source packages ship an affected version, including github.com/pinchtab/pinchtab. It affects 1 product.

Package	Affected	Fixed in
`github.com/pinchtab/pinchtab` Go	All versions	`0.8.4`
`github.com/pinchtab/pinchtab` Go	All versions	`0.8.4`
`github.com/pinchtab/pinchtab` Go	All versions	`0.8.4`

Products include Pinchtab Pinchtab.

How do I fix CVE-2026-33619?

Upgrade github.com/pinchtab/pinchtab to 0.8.4 or later.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-33619 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-33619 exists.

Sources

Also known as GHSA-xqq2-4j46-vwp7, GO-2026-4825.