CVE-2021-46875Network attack vector

Stored XSS via incomplete filetype blacklist

Published Mar 12, 2023 · Updated Mar 4, 2025

Stored XSS in eZ Platform Ibexa Kernel before 1.3.1.1 allows remote attackers to run script in victims' browsers via uploaded files. The default ezsettings.default.io.file_storage.file_type_blacklist omits common scriptable extensions, so HTML and JavaScript uploads pass the existing file-type restriction. Execution requires a victim to open the uploaded file's link, after which the script runs in the affected site's browser origin and can read or alter page data.

CVSS severity6.1
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in eZ Platform Ibexa Kernel before 1.3.1.1 allows remote attackers to run script in victims' browsers via uploaded files. The default ezsettings.default.io.file_storage.file_type_blacklist omits common scriptable extensions, so HTML and JavaScript uploads pass the existing file-type restriction. Execution requires a victim to open the uploaded file's link, after which the script runs in the affected site's browser origin and can read or alter page data.

The record

CVE
CVE-2021-46875
Published
Mar 12, 2023
Updated
Mar 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

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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