CVE-2022-4839Public exploitNetwork attack vector

Stored script execution via unescaped strikethrough text

Published Dec 29, 2022 · Updated Apr 9, 2025

Stored XSS in the Markdown renderer in Memos 0.9.0 and earlier allows remote authenticated users to execute script in viewers. The strikethrough parser inserts memo text into a del element without HTML escaping, so crafted Markdown persists active markup. A user must store the payload and another user must view the rendered memo; script execution is confined to the viewer's browser context.

CVSS severity8.0
High
EPSS probability0.77%
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 the Markdown renderer in Memos 0.9.0 and earlier allows remote authenticated users to execute script in viewers. The strikethrough parser inserts memo text into a del element without HTML escaping, so crafted Markdown persists active markup. A user must store the payload and another user must view the rendered memo; script execution is confined to the viewer's browser context.

The record

CVE
CVE-2022-4839
Published
Dec 29, 2022
Updated
Apr 9, 2025
Vendor
Memos
Product
Memos
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 29, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 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 <0.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Memos · Memosversion=unspecified <0.9.1

Published CVSS scores

8.0huntr.devCVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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