Description
BentoPDF is a client-side PDF toolkit that is self hostable. In 2.8.6 and earlier, the certificate and timestamp CORS proxy in cloudflare/cors-proxy-worker.js uses isPrivateOrReservedHost() to validate a supplied hostname separately from the DNS resolution used by fetch(targetUrl), allowing an attacker-controlled hostname to resolve to an internal or reserved destination after validation. A certificate-like path can satisfy ALLOWED_PATH_PATTERNS, and direct clients can forge the browser-oriented Origin header. Deployments without PROXY_SECRET skip the optional signature check, while the signature is an anti-abuse measure rather than a destination-security boundary. The proxy has a 10 MB response limit and can relay response bodies from reachable destinations. The advisory identifies both the official Worker deployment and self-hosted instances as impacted where the Worker execution environment can reach internal or reserved destinations. This vulnerability is fixed in 2.8.7.
Published: 2026-09-24
Score: 8.6 High
EPSS: n/a
KEV: No
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 24 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 24 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Description BentoPDF is a client-side PDF toolkit that is self hostable. In 2.8.6 and earlier, the certificate and timestamp CORS proxy in cloudflare/cors-proxy-worker.js uses isPrivateOrReservedHost() to validate a supplied hostname separately from the DNS resolution used by fetch(targetUrl), allowing an attacker-controlled hostname to resolve to an internal or reserved destination after validation. A certificate-like path can satisfy ALLOWED_PATH_PATTERNS, and direct clients can forge the browser-oriented Origin header. Deployments without PROXY_SECRET skip the optional signature check, while the signature is an anti-abuse measure rather than a destination-security boundary. The proxy has a 10 MB response limit and can relay response bodies from reachable destinations. The advisory identifies both the official Worker deployment and self-hosted instances as impacted where the Worker execution environment can reach internal or reserved destinations. This vulnerability is fixed in 2.8.7.
Title BentoPDF: SSRF in cors-proxy-worker.js via DNS-based hostname allowlist bypass
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-24T15:37:29.237Z

Reserved: 2026-08-20T20:35:30.148Z

Link: CVE-2026-77581

cve-icon Vulnrichment

Updated: 2026-09-24T15:37:26.759Z

cve-icon NVD

Status : Received

Published: 2026-09-24T16:17:10.943

Modified: 2026-09-24T16:17:10.943

Link: CVE-2026-77581

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-918

    Server-Side Request Forgery (SSRF)