CVE-2026-102354 BentoPDF: SSRF via DNS Rebinding (TOCTOU) in Cloudflare CORS Proxy Worker
Attacker can exploit DNS rebinding in BentoPDF's Cloudflare proxy to access internal network resources when proxy secret validation is disabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-102354?
CVE-2026-102354 is a medium-severity server-side request forgery vulnerability in alam00000 bentopdf, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
BentoPDF is a privacy-focused PDF toolkit that runs in the browser. In versions through 2.8.6, cloudflare/cors-proxy-worker.js performs a DNS-over-HTTPS safety check in hostnameResolvesToPrivate(), as used by isValidCertificateUrl() and isValidTsaUrl(), separately from the outbound fetch(targetUrl, ...). In deployments where PROXY_SECRET validation is not enabled, a direct client that controls authoritative DNS can forge the Origin header, supply a certificate, OCSP, CRL, or TSA URL that passes the proxy's accepted path checks, return a public address during validation, and return a private or link-local address during the later fetch. The endpoint can return allowed response bodies to the attacker, but exploitation requires precise timing, redirects and IP-literal obfuscation are blocked, and network reachability limits the target. This vulnerability is fixed in 2.8.7.
Which versions are affected by CVE-2026-102354?
How do I fix CVE-2026-102354?
No fix has been published for CVE-2026-102354 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-102354 being exploited?
There is no known exploitation of CVE-2026-102354 in the wild and no public exploit code.
Sources
Also known as GHSA-wh78-rcw2-hhg9.