advplyr audiobookshelf up to 2.33.1 ZIP File /api/backups/upload zip.entryData data amplification

Summaryinfo

A vulnerability categorized as problematic has been discovered in advplyr audiobookshelf up to 2.33.1. The impacted element is the function zip.entryData of the file /api/backups/upload of the component ZIP File Handler. Executing a manipulation can lead to data amplification. This vulnerability is handled as CVE-2026-42886. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in advplyr audiobookshelf up to 2.33.1 and classified as problematic. This vulnerability affects the function zip.entryData of the file /api/backups/upload of the component ZIP File Handler. The manipulation with an unknown input leads to a data amplification vulnerability. The CWE definition for the vulnerability is CWE-409. The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-42886 since 04/30/2026. The exploitation appears to be easy. The attack can be initiated remotely. The exploitation needs additional levels of successful authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 2.33.2 eliminates this vulnerability.

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Productinfo

Vendor

• advplyr

Name

• audiobookshelf

Version

• 2.33.0
• 2.33.1

Website

• Product: https://github.com/advplyr/audiobookshelf/

CPE 2.3info

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CPE 2.2info

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