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GHSA-2h8j-8r9p-849f
No affected components available
Overview
A type confusion issue exists in the @digitalocean/do-markdownit package. In the callout and fence_environment plugins, the allowedClasses and allowedEnvironments options are expected to be arrays of strings. If these options are provided as a single string, the code applies .includes directly on the string, resulting in substring matching instead of membership checks against an array.
Affected Versions
All versions up to and including 1.16.1 (npm).
Impact
Supplying crafted input can bypass intended allow-lists (e.g., class/environment constraints) due to substring checks, which may enable rendering of unintended classes or environments and lead to policy bypass in downstream consumers.
Mitigation
Until an upstream fix is released, ensure configuration normalization before invoking the plugins:
- Validate that
allowedClassesandallowedEnvironmentsare arrays (Array.isArray(...)), converting single strings into one-element arrays when necessary. - Consider sanitizing or strictly validating user-controlled values that influence Markdown rendering.
The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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