WordPress plugin "Markdown on Save Improved" vulnerable to cross-site scripting


The WordPress plugin "Markdown on Save Improved" contains a stored cross-site scripting (CWE-79) vulnerability.

Kenta Yamamoto of Cryptography Laboratory,Department of Information and Communication Engineering, Graduate School of Tokyo Denki University reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.
CVSS Severity (What is CVSS?)

CVSS V3 Severity:
Base Metrics 5.4 (Medium) [IPA Score]
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: Low
  • User Interaction: Required
  • Scope: Changed
  • Confidentiality Impact: Low
  • Integrity Impact: Low
  • Availability Impact: None
CVSS V2 Severity:
Base Metrics 4.0 (Medium) [IPA Score]
  • Access Vector: Network
  • Access Complexity: Low
  • Authentication: Single Instance
  • Confidentiality Impact: None
  • Integrity Impact: Partial
  • Availability Impact: None
Affected Products

Markdown on Save Improved
  • Markdown on Save Improved version 2.5 and earlier


An arbitrary script may be executed on the user's web browser.

[Update the plugin]
Update the plugin according to the information provided by the developer.

While the developer provided an update for this vulnerability, the developer states that this plugin is deprecated. Fixes may not be provided in the future, so it is recommended to transition to a different module.
Vendor Information

Markdown on Save Improved
CWE (What is CWE?)

  1. Cross-site Scripting(CWE-79) [IPA Evaluation]
CVE (What is CVE?)

  1. CVE-2016-4812

  1. JVN : JVN#26026353
  2. National Vulnerability Database (NVD) : CVE-2016-4812
Revision History

  • [2016/05/25]
      Web page was published
      References : Content was added