CVE-2023-28626
Quadratic runtime when parsing Markdown in comrak
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Quadratic runtime when parsing Markdown in comrak
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
- Record
CVE-2023-28626- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2023-0947
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
- Record
EUVD-2023-0947- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8hqf-xjwp-p67v
Comrak vulnerable to quadratic runtime issues when parsing Markdown (GHSL-2023-047)
Impact
A range of quadratic parsing issues from cmark/cmark-gfm are also present in Comrak. These can be used to craft denial-of-service attacks on services that use Comrak to parse Markdown.
Patches
0.17.0 contains fixes to known quadratic parsing issues.
Workarounds
n/a
References
- https://github.com/commonmark/cmark/issues/255
- https://github.com/commonmark/cmark/issues/389
- https://github.com/commonmark/cmark/issues/373
- https://github.com/commonmark/cmark/issues/299
- https://github.com/commonmark/cmark/issues/388
- https://github.com/commonmark/cmark/issues/284
- 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
- Record
GHSA-8hqf-xjwp-p67v- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
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
- Record
CVE-2023-28626- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
Quadratic runtime when parsing Markdown in comrak
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
- Record
CVE-2023-28626- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVGHSA-8hqf-xjwp-p67v
Comrak vulnerable to quadratic runtime issues when parsing Markdown (GHSL-2023-047)
Impact
A range of quadratic parsing issues from cmark/cmark-gfm are also present in Comrak. These can be used to craft denial-of-service attacks on services that use Comrak to parse Markdown.
Patches
0.17.0 contains fixes to known quadratic parsing issues.
Workarounds
n/a
References
- https://github.com/commonmark/cmark/issues/255
- https://github.com/commonmark/cmark/issues/389
- https://github.com/commonmark/cmark/issues/373
- https://github.com/commonmark/cmark/issues/299
- https://github.com/commonmark/cmark/issues/388
- https://github.com/commonmark/cmark/issues/284
- 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
- Record
GHSA-8hqf-xjwp-p67v- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-400
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
comrakcrates.io |
before 0.17.0 | 0.17.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-28626 is a medium vulnerability (CVSS 5.3) in Comrak Project Comrak, published March 28, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.12%, the 66th percentile. Fixed in comrak 0.17.0.
References
github.com/kivikakk/comrak/security/advisories/GHSA-8hqf-xjwp-p67v
lists.fedoraproject.org/archives/list/[email protected]/message/PTWZWCT7KCX2KTXTLPUYZ3EHOONG4X46
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nvd.nist.gov/vuln/detail/CVE-2023-28626