fix(nextjs): Strictly validate tunnel target parameters

[lforst]

No description provided.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	77.43 KB (0%)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	66.49 KB (0%)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	30.97 KB (0%)
@sentry/browser - Webpack (gzipped)	21.29 KB (0%)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.79 KB (+0.19% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	29.09 KB (+0.45% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	21.23 KB (+0.48% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	216.85 KB (+0.21% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	88.28 KB (+0.5% 🔺)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	63.28 KB (+0.7% 🔺)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	31.8 KB (+0.19% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	77.82 KB (0%)
@sentry/react - Webpack (gzipped)	21.34 KB (0%)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	94.15 KB (0%)
@sentry/nextjs Client - Webpack (gzipped)	47.86 KB (0%)

[dominikjasek]

🍿

[hueypeard]

Is it obvious what the impact of this is? Are there any attackers utilising this in the wild? I understand it is probably not a great design choice and the validation should have been stronger, but it would be great to get an idea of exposure

[sreetamdas]

@hueypeard this was published earlier today: https://blog.sentry.io/next-js-sdk-security-advisory-cve-2023-46729/

[lforst]

@hueypeard Seconding what @sreetamdas mentioned. We wrote up an FAQ with everything we could think of that might be relevant to the vulnerability. If you're still missing information, let us know how we can improve it!