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CVE-2026-108587 — WordPress

CRITICAL

CVE-2026-108587 is a critical-severity (CVSS 9.8) Unrestricted File Upload vulnerability. No vendor fix is recorded yet; mitigation options are listed below.

The 10Web Booster – Website speed optimization, Cache & Page Speed optimizer plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 2.34.10…

Published
Updated
Affected
—
Patched
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Exploits
None indexed
Exploitation data as of Oct 15, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Description

The 10Web Booster – Website speed optimization, Cache & Page Speed optimizer plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 2.34.10 via the compressCustom function. This is due to missing file type validation and extension filtering on the page_id parameter, combined with a world-readable leaked nonce that bypasses authentication checks. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. This exploit chain requires obtaining the plugin's REST nonce (tenwebio_rest), which is automatically serialized to a world-readable file under wp-content/uploads/ whenever a bulk optimisation batch pauses; because the nonce is generated in a cron/loopback context with a user ID of 0, it is valid for unauthenticated visitors.

Detection & mitigation playbook

Vulnerability

  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Remediation status

    No fixed release is recorded for CVE-2026-108587 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.

Frequently Asked Questions

The 10Web Booster – Website speed optimization, Cache & Page Speed optimizer plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 2.34.10 via the compressCustom function. This is due to missing file type validation and extension filtering on the page_id parameter, combined with a world-readable leaked nonce that bypasses authentication checks. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. This exploit chain requires obtaining the plugin's REST nonce (tenwebio_
O3 Security · Impact-Aware SCA

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CVE-2026-108587: WordPress (Critical 9.8)