BentoPDF: SSRF in cors-proxy-worker.js via DNS-based hostname allowlist bypass (CVE-2026-77581) | HOL Guard CVE

High · CVSS 8.6CVE-2026-77581

BentoPDF: SSRF in cors-proxy-worker.js via DNS-based hostname allowlist bypass

Answer in brief

CVE-2026-77581 records a High severity (CVSS 8.6) vulnerability in BentoPDF: SSRF in cors-proxy-worker.js via DNS-based hostname allowlist bypass. The current sources do not mark it as known exploited. The current feed maps alam00000/bentopdf (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.6
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps alam00000/bentopdf (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
alam00000/bentopdfgeneric	<2.8.7	2.8.7

Recommended response

Check inventory. Check lockfiles and deployed manifests for alam00000/bentopdf.
Review the reported fix. Update alam00000/bentopdf to 2.8.7 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.