CVE-2026-102354

BentoPDF: SSRF via DNS Rebinding (TOCTOU) in Cloudflare CORS Proxy Worker

Published Oct 14, 2026 CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Alam00000
Alam00000 bentopdf
Vendors & Products Alam00000
Alam00000 bentopdf
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title BentoPDF: SSRF via DNS Rebinding (TOCTOU) in Cloudflare CORS Proxy Worker
Weaknesses CWE-367
CWE-918
References
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 15, 2026, 4:19 PM
Reserved
Sep 28, 2026, 10:38 PM
Status
Deferred
Published
Oct 14, 2026, 7:17 PM
Modified
Oct 15, 2026, 5:17 PM