CVE-2022-31108

CVE-2022-31108 is a medium-severity vulnerability in Mermaid Project Mermaid with a CVSS 3.x base score of 4.1. 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

Description

Mermaid is a JavaScript based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams. An attacker is able to inject arbitrary `CSS` into the generated graph allowing them to change the styling of elements outside of the generated graph, and potentially exfiltrate sensitive information by using specially crafted `CSS` selectors. The following example shows how an attacker can exfiltrate the contents of an input field by bruteforcing the `value` attribute one character at a time. Whenever there is an actual match, an `http` request will be made by the browser in order to "load" a background image that will let an attacker know what's the value of the character. This issue may lead to `Information Disclosure` via CSS selectors and functions able to generate HTTP requests. This also allows an attacker to change the document in ways which may lead a user to perform unintended actions, such as clicking on a link, etc. This issue has been resolved in version 9.1.3. Users are advised to upgrade. Users unable to upgrade should ensure that user input is adequately escaped before embedding it in CSS blocks.

Frequently asked questions

What is CVE-2022-31108?
Mermaid is a JavaScript based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams. An attacker is able to inject arbitrary `CSS` into the generated graph allowing them to change the styling of elements outside of the generated graph, and potentially exfiltrate sensitive information by using specially crafted `CSS` selectors. The following example shows how an attacker can exfiltrate the contents of an input field by bruteforcing the `value` attribute one character at a time. Whenever there is an actual match, an `http` request will be made by the browser in order to "load" a background image that will let an attacker know what's the value of the character. This issue may lead to `Information Disclosure` via CSS selectors and functions able to generate HTTP requests. This also allows an attacker to change the document in ways which may lead a user to perform unintended actions, such as clicking on a link, etc. This issue has been resolved in version 9.1.3. Users are advised to upgrade. Users unable to upgrade should ensure that user input is adequately escaped before embedding it in CSS blocks.
How severe is CVE-2022-31108?
CVE-2022-31108 has a CVSS 3.x base score of 4.1, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2022-31108 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-31108?
CVE-2022-31108 affects Mermaid Project Mermaid. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-31108?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2022-31108 published?
CVE-2022-31108 was published on 2022-06-28 and last updated on 2026-06-17.

References

Affected products (1)

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