CVE-2018-1000874

Severity: medium (CVSS 6.1 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2018-12-20 · updated 2026-06-17
Weakness: CWE-79

Description

PHP cebe markdown parser version 1.2.0 and earlier contains a Cross Site Scripting (XSS) vulnerability in all distributed parsers allowing a malicious crafted script to be executed that can result in the lose of user data and sensitive user information. This attack can be exploited by crafting a three backtick wrapped payload with a character in front: L: "```<script>alert();</script>```". NOTE: This has been argued as a non-issue (see references) since it is not the parser's job to sanitize malicious code from a parsed document

Affected products

Cebe Markdown: through 1.2.0

References

https://github.com/cebe/markdown/issues/166
https://github.com/cebe/markdown/issues/166#issuecomment-508230493
https://github.com/cebe/markdown/issues/166
https://github.com/cebe/markdown/issues/166#issuecomment-508230493

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