What is CVE-2026-42886?

CVE-2026-42886 is a medium-severity vulnerability in Advplyr Audiobookshelf, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 4.9/10. Published 2026-05-11.

How severe is CVE-2026-42886?

Medium severity. CVSS v3 base score is 4.9 out of 10.

Vulnerability in Advplyr Audiobookshelf

CVE-2026-42886

Audiobookshelf is a self-hosted audiobook and podcast server. Prior to 2.32.2, the POST /api/backups/upload endpoint decompresses the details entry from an uploaded .audiobookshelf ZIP file entirely into memory using zip.entryData(), with no limit on the decompressed size. The upload middleware also has no file size limit. An admin user can upload a crafted ZIP containing a highly compressed details entry that, when decompressed, consumes hundreds of megabytes or gigabytes of memory, crashing the server process via out-of-memory. This vulnerability is fixed in 2.32.2.

EPSS: 0.003 (17.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.

Affected products

Advplyr Audiobookshelf — versions < 2.33.2

Weakness classification (CWE)

CWE-409 — Improper Handling of Highly Compressed Data (Data Amplification)

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-42886?: CVE-2026-42886 is a medium-severity vulnerability in Advplyr Audiobookshelf, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 4.9/10. Published 2026-05-11.
How severe is CVE-2026-42886?: Medium severity. CVSS v3 base score is 4.9 out of 10.