CVE-2023-28631 Attacker controlled data in AST nodes is not validated in comrak
Attackers can cause crashes or undefined behavior in the comrak Rust library by providing invalid UTF-8 data in manually constructed AST nodes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-28631?
CVE-2023-28631 is a medium-severity vulnerability in kivikakk comrak, published on 28 Mar 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
comrak is a CommonMark + GFM compatible Markdown parser and renderer written in rust. 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. Version 0.17.0 contains adjustments to the AST, storing strings instead of unvalidated byte arrays. Users are advised to upgrade. Users unable to upgrade may manually validate UTF-8 correctness of all data when assigning to `&[u8]` and `Vec<u8>` fields in the AST. This issue is also tracked as `GHSL-2023-049`.
Weakness: CWE-755
Which versions are affected by CVE-2023-28631?
2 open source packages ship an affected version, including comrak. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
comrak crates.io | All versions | 0.17.0 |
comrak crates.io | All versions | 0.17.0 |
Products include Comrak Project Comrak.
How do I fix CVE-2023-28631?
Upgrade comrak to 0.17.0 or later.
Is CVE-2023-28631 being exploited?
There is no known exploitation of CVE-2023-28631 in the wild and no public exploit code.
Other vulnerabilities in kivikakk comrak
Sources
Also known as GHSA-5r3x-p7xx-x6q5.