Readest is a modern, feature-rich ebook reader designed for seamless cross-platform access and an…

Why it is Amber

• CVSS 9.3 critical
• Remotely exploitable without logging in

References

• https://github.com/readest/readest/commit/495783d04516d05b2eb10f8f8bad297d436b36de
• https://github.com/readest/readest/pull/4638
• https://github.com/readest/readest/releases/tag/v0.11.10
• https://github.com/readest/readest/security/advisories/GHSA-c7mm-g2j2-98cx

Original description

Readest is a modern, feature-rich ebook reader designed for seamless cross-platform access and an intuitive reading experience. Prior to 0.11.10, the unauthenticated /api/opds/proxy route in apps/readest-app/src/app/api/opds/proxy/route.ts accepted an attacker-controlled URL and fetched it server-side without restricting the scheme, blocking private, loopback, link-local, or metadata hosts, or revalidating destinations during automatic redirect following. The route also accepted caller-controlled outbound headers and Authorization values and reflected the upstream status and response body. A remote attacker could use the service as an open request proxy and, on Node, Docker, or other self-hosted deployments with internal-network access, retrieve cloud metadata or internal-service responses. Cloudflare Workers deployments restrict access to link-local and private destinations, which reduces the internal-network impact there, but the unauthenticated public fetch-and-reflect behavior remains. This issue is fixed in version 0.11.10.