Server-side request forgery in Readest OPDS proxy
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Readest before 0.11.10 has a server-side request forgery flaw (CWE-918) in its unauthenticated /api/opds/proxy route. It fetches a caller-supplied URL server-side without restricting the scheme or blocking private or metadata hosts. A remote attacker can use it as an open proxy to reach cloud metadata or internal services on Node, Docker, or self-hosted deployments. Cloudflare Workers blocks link-local and private destinations, but public fetch-and-reflect remains.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade Readest to version 0.11.10, the fixed version. Versions before 0.11.10 are affected.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA readest (readest) Fixed in 0.11.10
Timeline
- 2026-11-04 Threatist record created from CVE-2026-57566
- 2026-11-05 CISA SSVC decision points changed
- 2026-11-05 Priority changed: MEDIUM → HIGH
References
More readest vulnerabilities
- TI-2026-85222 Path traversal in Readest Tauri commands allows arbitrary file access CVSS 3.1HIGH 8.6
- TI-2026-85220 Path traversal in Readest upload overwrites other users' books CVSS 3.1MEDIUM 6.5
- TI-2026-85219 Authorization bypass in Readest lets users hijack paid subscriptions CVSS 3.1MEDIUM 6.5
- TI-2026-56980 Readest: unsanitized iframe srcdoc attribute in the EPUB sanitizer can lead to arbitrary code execution CVSS 3.1HIGH 8.8
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences