CVE-2021-38186
Cross-site Scripting in comrak
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
- Record
CVE-2021-38186- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
- Record
CVE-2021-38186- Updated
- 2026-11-02
EUVDEUVD-2021-1606 No score
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
- Record
EUVD-2021-1606- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-6wj2-g87r-pm62
Cross-site Scripting in comrak
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
- Record
GHSA-6wj2-g87r-pm62- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
- Record
CVE-2021-38186- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-6wj2-g87r-pm62
Cross-site Scripting in comrak
An issue was discovered in the comrak crate before 0.10.1 for Rust. It mishandles & characters, leading to XSS via &# HTML entities.
- Record
GHSA-6wj2-g87r-pm62- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVRUSTSEC-2021-0063 No score
XSS in `comrak`
comrak operates by default in a "safe" mode of operation where unsafe content, such as arbitrary raw HTML or URLs with non-standard schemes, are not permitted in the output. This is per the reference GFM implementation, cmark-gfm.
Ampersands were not being correctly escaped in link targets, making it possible
to fashion unsafe URLs using schemes like data: or javascript: by entering
them as HTML entities, e.g. data:. The intended
behaviour, demonstrated upstream, is that these should be escaped and therefore
harmless, but this behaviour was broken in comrak.
- Record
RUSTSEC-2021-0063- Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-38186 is a medium vulnerability (CVSS 6.1) in Comrak Project Comrak, published May 4, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.74%, the 54th percentile. Fixed in comrak 0.10.1.
References
rustsec.org/advisories/RUSTSEC-2021-0063.html
raw.githubusercontent.com/rustsec/advisory-db/main/crates/comrak/RUSTSEC-2021-0063.md
nvd.nist.gov/vuln/detail/CVE-2021-38186
github.com/kivikakk/comrak/releases/tag/0.10.1
crates.io/crates/comrak