CVE-2024-35540Public exploitNetwork attack vector

Administrator compromise via unsanitized post preview

Published Aug 20, 2024 · Updated Aug 20, 2024

Stored XSS in Typecho 1.3.0 allows remote authenticated users with post-writing privileges to run scripts in an administrator's browser. The contents-post-edit endpoint stores the text parameter without neutralizing an img onerror handler, and preview.php renders that handler in the post preview. A contributor must save a crafted post and induce an administrator to open its preview; the script then acts with the administrator's privileges and can modify application PHP code.

CVSS severity9.0
Critical
EPSS probability2.83%
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 Typecho 1.3.0 allows remote authenticated users with post-writing privileges to run scripts in an administrator's browser. The contents-post-edit endpoint stores the text parameter without neutralizing an img onerror handler, and preview.php renders that handler in the post preview. A contributor must save a crafted post and induce an administrator to open its preview; the script then acts with the administrator's privileges and can modify application PHP code.

The record

CVE
CVE-2024-35540
Published
Aug 20, 2024
Updated
Aug 20, 2024
Vendor
Typecho
Product
Typecho
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2024Record 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=1.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Typecho · Typechoversion=1.3.0

Published CVSS scores

7.6CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
9.0NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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 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')
T1204.001Malicious 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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