---
id: CVE-2026-57565
title: >-
  Readest: Cross-tenant object write via unsanitized fileName in
  /api/storage/upload (object-key path traversal)
summary: >-
  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 apps/readest-app/src/pages/api/storage/upload.ts route constructed an
  object key from t…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-22
vendor: readest
product: readest
affected:
  - readest < 0.11.10
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T20:05:26.746679Z'
exploitAvailable: true
published: '2026-11-04'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:11:46.274Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-57565'
references:
  - url: 'https://github.com/readest/readest/security/advisories/GHSA-mfmj-2frf-vhgw'
    label: 'https://github.com/readest/readest/security/advisories/GHSA-mfmj-2frf-vhgw'
  - url: 'https://github.com/readest/readest/pull/4638'
    label: 'https://github.com/readest/readest/pull/4638'
  - url: >-
      https://github.com/readest/readest/commit/495783d04516d05b2eb10f8f8bad297d436b36de
    label: >-
      https://github.com/readest/readest/commit/495783d04516d05b2eb10f8f8bad297d436b36de
  - url: 'https://github.com/readest/readest/releases/tag/v0.11.10'
    label: 'https://github.com/readest/readest/releases/tag/v0.11.10'
tags:
  - cve.org
  - exploit-available
epss: 0.01036
epssPercentile: 0.64096
ingestedAt: '2026-11-05T22:38:31.730Z'
---

## Overview

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 apps/readest-app/src/pages/api/storage/upload.ts route constructed an object key from the authenticated user's identifier and a client-controlled fileName without rejecting path separators or parent-directory traversal. In the R2 backend, apps/readest-app/src/utils/r2.ts placed that key into a new Request URL before signing it, and URL normalization collapsed parent-directory components so the resulting presigned PUT could escape the caller's namespace. An authenticated attacker who knew a target user identifier and book hash could overwrite or poison that user's stored book object and corrupt the associated file_key metadata; the exact cross-tenant escape was verified for the R2 backend. This issue is fixed in version 0.11.10.

## Affected

- `readest < 0.11.10`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.