# CVE-2023-42821: golang-github-gomarkdown-markdown: The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML

CVE-2023-42821 is fixed in golang-github-gomarkdown-markdown on 1 platform, first by DEBIAN-CVE-2023-42821, released September 22, 2023. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2023-42821
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0125
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 22, 2023

## Description

The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML. Prior to pseudoversion `0.0.0-20230922105210-14b16010c2ee`, which corresponds with commit `14b16010c2ee7ff33a940a541d993bd043a88940`, parsing malformed markdown input with parser that uses parser.Mmark extension could result in out-of-bounds read vulnerability. To exploit the vulnerability, parser needs to have `parser.Mmark` extension set. The panic occurs inside the `citation.go` file on the line 69 when the parser tries to access the element past its length. This can result in a denial of service. Commit `14b16010c2ee7ff33a940a541d993bd043a88940`/pseudoversion `0.0.0-20230922105210-14b16010c2ee` contains a patch for this issue.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | golang-github-gomarkdown-markdown Debian 13.5 (trixie) | 0.0~git20231115.a660076-1 | [DEBIAN-CVE-2023-42821](https://patchblox.com/security/data/fix/linux/debian-cve-2023-42821.md) | Sep 22, 2023 |
| Linux | golang-github-gomarkdown-markdown Debian 14 | 0.0~git20231115.a660076-1 | [DEBIAN-CVE-2023-42821](https://patchblox.com/security/data/fix/linux/debian-cve-2023-42821.md) | Sep 22, 2023 |

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