CVE-2023-0301Public exploitNetwork attack vector

Stored XSS via unrestricted Markdown link schemes

Published Jan 14, 2023 · Updated Apr 7, 2025

Stored cross-site scripting in alf.io before 2.0-M4-2301 allows remote authenticated users to execute script via crafted Markdown. MustacheCustomTag converts Markdown links to HTML but previously retained non-HTTP schemes instead of removing the resulting href attribute. A highly privileged user must store the link and another user must follow it; execution occurs in the victim's browser under the application's origin, exposing accessible data and actions.

CVSS severity5.4
Medium
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in alf.io before 2.0-M4-2301 allows remote authenticated users to execute script via crafted Markdown. MustacheCustomTag converts Markdown links to HTML but previously retained non-HTTP schemes instead of removing the resulting href attribute. A highly privileged user must store the link and another user must follow it; execution occurs in the victim's browser under the application's origin, exposing accessible data and actions.

The record

CVE
CVE-2023-0301
Published
Jan 14, 2023
Updated
Apr 7, 2025
Vendor
Alf.io
Product
alf.io
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jan 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 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=unspecified <Alf.io 2.0-M4-2301

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Alf.io · alf.ioversion=unspecified <Alf.io 2.0-M4-2301

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.3huntr.devCVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

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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