CVE-2021-26642Network attack vector

Authenticated code execution via unblocked PHAR uploads

Published Jan 20, 2023 · Updated Apr 3, 2025

Unrestricted file upload in XEHub XpressEngine 3.0.14 allows remote authenticated users to execute arbitrary server-side code. The Storage extension-to-MIME maps omit PHAR, so an uploaded PHAR image bypasses the executable-file filter and remains web-executable. A low-privileged bulletin-board account with image-upload access is required, and successful exploitation compromises the CMS server.

CVSS severity9.8
Critical
EPSS probability1.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in XEHub XpressEngine 3.0.14 allows remote authenticated users to execute arbitrary server-side code. The Storage extension-to-MIME maps omit PHAR, so an uploaded PHAR image bypasses the executable-file filter and remains web-executable. A low-privileged bulletin-board account with image-upload access is required, and successful exploitation compromises the CMS server.

The record

CVE
CVE-2021-26642
Published
Jan 20, 2023
Updated
Apr 3, 2025
Vendor
XEHub
Product
XpressEngine
Classifications
CWE-434, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2025Record 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=3.0.14 <=3.0.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

XEHub · XpressEngineversion=3.0.14 <=3.0.14

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8KrCERT/CCCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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