CVE-2026-42886Public exploitNetwork attack vector

Admin-only server crash via compressed backup expansion

Published May 11, 2026 · Updated May 11, 2026

Denial of service in Audiobookshelf before 2.33.2 allows remote authenticated users to crash the server via a crafted backup upload. The POST /api/backups/upload handler passes the ZIP details entry to zip.entryData(), expanding attacker-controlled compressed content entirely in memory without decompressed-size or upload-size limits. Administrator privileges are required, and successful exploitation terminates the server process through memory exhaustion, interrupting service for all users.

CVSS severity4.9
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Audiobookshelf before 2.33.2 allows remote authenticated users to crash the server via a crafted backup upload. The POST /api/backups/upload handler passes the ZIP details entry to zip.entryData(), expanding attacker-controlled compressed content entirely in memory without decompressed-size or upload-size limits. Administrator privileges are required, and successful exploitation terminates the server process through memory exhaustion, interrupting service for all users.

The record

CVE
CVE-2026-42886
Published
May 11, 2026
Updated
May 11, 2026
Vendor
advplyr
Product
Audiobookshelf
Classifications
CWE-409, T1499.004
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.33.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

advplyr · Audiobookshelfversion=< 2.33.2

Published CVSS scores

4.9GitHub CNACVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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