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HIGH

CVE-2026-71209

CVSS v3

7.5

HIGH

EPSS Score

1.9 %

exploit probability, as of 2026-09-25

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

audiobookshelf's authentication-exemption check (server/routers/Auth.js) matches unauthenticated-allowed GET routes against req.path via a regex requiring a literal /items/:id/cover or /authors/:id/image shape, where req.path retains %2F sequences URL-encoded. Express's router decodes the :id route parameter before handler code runs, so a %2F-encoded '../' sequence in :id (e.g. ..%2f..%2f..%2ftmp%2fpwned) passes the literal-path auth-exemption check while resolving to a real path-traversal paylo

Technical details

Published
2026-08-05
Last Modified
2026-08-05

Frequently asked questions

What is CVE-2026-71209?

audiobookshelf's authentication-exemption check (server/routers/Auth.js) matches unauthenticated-allowed GET routes against req.path via a regex requiring a literal /items/:id/cover or /authors/:id/image shape, where req.path retains %2F sequences URL-encoded. Express's router decodes the :id route parameter before handler code runs, so a %2F-encoded '../' sequence in :id (e.g. ..%2f..%2f..%2ftmp%2fpwned) passes the literal-path auth-exemption check while resolving to a real path-traversal paylo

Is CVE-2026-71209 actively exploited?

Active exploitation of CVE-2026-71209 has not been confirmed. Its EPSS score was 1.9% on 2026-09-25, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-71209?

CVE-2026-71209 has a CVSS v3 base score of 7.5 (HIGH severity).

Is CVE-2026-71209 affecting your environment?

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