CVE-2026-57565Readest: Cross-tenant object write via unsanitized fileName in /api/storage/upload (object-key path traversal)
- 6.5MediumCVSS base score
- 1.0%Exploitation in 30 daysEPSS · top 36% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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 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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/readest/readest/security/advisories/GHSA-mfmj-2frf-vhgw (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 4 months later
· 4 months later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 1.0% · top 36% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
References
References4
- https://github.com/readest/readest/security/advisories/GHSA-mfmj-2frf-vhgw (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/readest/readest/pull/4638 (opens in a new tab)x_refsource_MISC
- https://github.com/readest/readest/commit/495783d04516d05b2eb10f8f8bad297d436b36de (opens in a new tab)x_refsource_MISC
- https://github.com/readest/readest/releases/tag/v0.11.10 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-117185 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-57565)Record last updated .