CVE-2023-25154Network attack vector

Browser script execution via unvalidated ActivityPub URI

Published Feb 22, 2023 · Updated Mar 10, 2025

Cross-site scripting in Misskey before 13.5.0 allows remote attackers to execute JavaScript in a recipient's browser via ActivityPub. The instance-source link shown for a federated user or note accepts an ActivityPub URI using the javascript scheme and renders it as a clickable link without validating the scheme. Exploitation requires the recipient to choose “view on remote” for attacker-controlled federated content, enabling script execution in the recipient's Misskey context.

CVSS severity7.1
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Misskey before 13.5.0 allows remote attackers to execute JavaScript in a recipient's browser via ActivityPub. The instance-source link shown for a federated user or note accepts an ActivityPub URI using the javascript scheme and renders it as a clickable link without validating the scheme. Exploitation requires the recipient to choose “view on remote” for attacker-controlled federated content, enabling script execution in the recipient's Misskey context.

The record

CVE
CVE-2023-25154
Published
Feb 22, 2023
Updated
Mar 10, 2025
Vendor
Misskey Project
Product
Misskey
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 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=< 13.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Misskey Project · Misskeyversion=< 13.5.0

Published CVSS scores

7.1GitHub CNACVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
6.1NVDCVSS: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')
T1203Exploitation for Client Execution

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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