CVE-2018-1000874
CVE-2018-1000874 is a medium-severity vulnerability in Cebe Markdown with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.
Key facts
- Severity: Medium (CVSS 3.x base score 6.1)
- CVSS v2: 4.3
- EPSS exploit prediction: 1% (52nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-79
- Affected product: Cebe Markdown
- Published:
- Last modified:
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
Frequently asked questions
- What is CVE-2018-1000874?
- 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
- How severe is CVE-2018-1000874?
- CVE-2018-1000874 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
- Is CVE-2018-1000874 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2018-1000874?
- CVE-2018-1000874 affects Cebe Markdown. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2018-1000874?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2018-1000874 published?
- CVE-2018-1000874 was published on 2018-12-20 and last updated on 2026-06-17.
References
- https://github.com/cebe/markdown/issues/166
- https://github.com/cebe/markdown/issues/166#issuecomment-508230493
Affected products (1)
- cpe:2.3:a:cebe:markdown:*:*:*:*:*:*:*:*
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