Quadratic runtime when parsing Markdown in comrak
Priority MEDIUM 41CWE-400Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-400.
Summary
comrak is a CommonMark + GFM compatible Markdown parser and renderer written in rust. A range of quadratic parsing issues are present in Comrak. These can be used to craft denial-of-service attacks on services that use Comrak to parse Markdown. This issue has been addressed in version 0.17.0. Users are advised to upgrade. There are no known workarounds for this vulnerability. This issue is also tracked as `GHSL-2023-047`
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0112 66th percentileScored 2026-11-07
Fix Fixed comrak (kivikakk): 0.17.0comrak (crates.io): 0.17.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| kivikakk | comrak | before 0.17.0 | 0.17.0 | Patch available | CNA |
| — | comrak (crates.io) | before 0.17.0 | 0.17.0 | Patch available | GHSA-8hqf-xjwp-p67v |
- comrak Vendorkivikakk Affected before 0.17.0 Fixed in 0.17.0 Patch available CNA
- comrak (crates.io) Vendor— Affected before 0.17.0 Fixed in 0.17.0 Patch available GHSA-8hqf-xjwp-p67v
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:comrak_project:comrak:*:*:*:*:*:rust:*:* | before 0.17.0 | Vulnerable | Comrak Project |
- cpe:2.3:a:comrak_project:comrak:*:*:*:*:*:rust:*:* Versions before 0.17.0 Vulnerable ·Comrak Project
Remediation
- Fix · CNA comrak (kivikakk) Fixed in 0.17.0
- Fix · GHSA-8hqf-xjwp-p67v comrak (crates.io) Fixed in 0.17.0 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2023-28626
- 2026-10-03 Alias added: GHSA-8hqf-xjwp-p67v
References
Advisory 2
Other 18
- https://lists.fedoraproject.org/archives/list/[email protected]/message/PTWZWCT7KCX2KTXTLPUYZ3EHOONG4X46/
- https://lists.fedoraproject.org/archives/list/[email protected]/message/OUYME2VA555X6567H7ORIJQFN4BVGT6N/
- https://lists.fedoraproject.org/archives/list/[email protected]/message/VQ3UBC7LE4VPCMZBTADIBL353CH7CPVV/
- https://github.com/commonmark/cmark/issues/389
- https://github.com/commonmark/cmark/issues/388
- https://github.com/commonmark/cmark/issues/373
- https://github.com/commonmark/cmark/issues/299
- https://github.com/commonmark/cmark/issues/284
- https://github.com/commonmark/cmark/issues/255
- https://github.com/commonmark/cmark/issues/218
- https://github.com/commonmark/cmark/pull/232
- https://github.com/github/cmark-gfm/blob/c32ef78bae851cb83b7ad52d0fbff880acdcd44a/test/pathological_tests.py#L63-L65
- https://github.com/github/cmark-gfm/blob/c32ef78bae851cb83b7ad52d0fbff880acdcd44a/test/pathological_tests.py#L87-L89
- https://github.com/kivikakk/comrak
- https://github.com/kivikakk/comrak/releases/tag/0.17.0
- https://lists.fedoraproject.org/archives/list/[email protected]/message/OUYME2VA555X6567H7ORIJQFN4BVGT6N
- https://lists.fedoraproject.org/archives/list/[email protected]/message/PTWZWCT7KCX2KTXTLPUYZ3EHOONG4X46
- https://lists.fedoraproject.org/archives/list/[email protected]/message/VQ3UBC7LE4VPCMZBTADIBL353CH7CPVV
More Comrak Project Comrak vulnerabilities
- TI-2023-13150 Attacker controlled data in AST nodes is not validated in comrak CVSS 3.1CRITICAL 9.8
- TI-2021-15863 An issue was discovered in the comrak crate before 0.10.1 for Rust. CVSS 3.1MEDIUM 6.1
- TI-2021-09116 An issue was discovered in the comrak crate before 0.9.1 for Rust. CVSS 3.1MEDIUM 6.1
Sources
- CVE-2023-28626 · CVE Program
- CVE-2023-28626 · NVD
- FIRST EPSS
- GHSA-8hqf-xjwp-p67v · GitHub Advisory Database · CC BY 4.0
- CVE-2023-28626 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences