A vulnerability was found in CodeMirror up to 5.17.0 and classified as problematic. Affected by this issue is some unknown functionality of the file mode/markdown/markdown.js of the component Markdown Mode. The manipulation leads to inefficient regular expression complexity. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Not all code samples mentioned in the GitHub issue can be found. The repository mentions, that "CodeMirror 6 exists, and is [...] much more actively maintained." - While the issue was reported up to version 5.17.0, the problematic patterns persisted in versions after that. In version 6.x, the issue has been resolved.