Summary
Comrak AST node data is not validated (GHSL-2023-049)
Workarounds
- Validate UTF-8 correctness of all data when assigning to
&[u8]andVec<u8>fields in the AST.
References
n/a
Impact
A Comrak AST can be constructed manually by a program instead of parsing a Markdown document with parse_document. This AST can then be converted to HTML via html::format_document_with_plugins. However, the HTML formatting code assumes that the AST is well-formed. For example, many AST notes contain [u8] fields which the formatting code assumes is valid UTF-8 data. Several bugs can be triggered if this is not the case.
CVE-2023-28631 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.17.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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0.17.0 contains adjustments to the AST, storing strings instead of unvalidated byte arrays.
Frequently Asked Questions
- What is CVE-2023-28631? CVE-2023-28631 is a medium-severity security vulnerability in comrak (rust), affecting versions < 0.17.0. It is fixed in 0.17.0.
- How severe is CVE-2023-28631? CVE-2023-28631 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of comrak are affected by CVE-2023-28631? comrak (rust) versions < 0.17.0 is affected.
- Is there a fix for CVE-2023-28631? Yes. CVE-2023-28631 is fixed in 0.17.0. Upgrade to this version or later.
- Is CVE-2023-28631 exploitable, and should I be worried? Whether CVE-2023-28631 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-28631 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2023-28631? Upgrade
comrakto 0.17.0 or later.