CVE-2021-28834 — Remote code execution in kramdown — CVE Details
Remote code execution in Kramdown
Summary
Advisory Timeline
- First published March 29, 2021 (2023 days ago).
- Last revised February 17, 2024 — 1055 days after initial publication.
Remediation
Upgrade to the fixed version using your package manager.
gem install kramdown -v 2.3.1
After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.
Affected Packages (1)
Affects 1 ecosystem: rubygems (1).
| Package | Ecosystem | Affected | Fixed In |
|---|---|---|---|
| kramdown | rubygems | 1.16.0, 1.16.1, 1.16.2, 1.17.0 (+7 more) | 2.3.1 |
Vulnerability Classification
Common Weakness Enumeration (CWE) identifiers for this vulnerability type.
- CWE-94Code InjectionMITRE
CVSS Score Breakdown
What the CVSS (Common Vulnerability Scoring System) 9.8 score means for each attack dimension.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://nvd.nist.gov/vuln/detail/CVE-2021-28834ADVISORY
- https://github.com/gettalong/kramdown/pull/708WEB
- https://github.com/stanhu/kramdown/commit/d6a1cbcb2caa2f8a70927f176070d126b2422760WEB
- https://github.com/stanhu/kramdown/commit/ff0218aefcf00cd5a389e17e075d36cd46d011e2WEB
- https://about.gitlab.com/releases/2021/03/17/security-release-gitlab-13-9-4-released/#remote-code-execution-via-unsafe-user-controlled-markdown-rendering-optionsWEB
- https://github.com/gettalong/kramdown/compare/REL_2_3_0...REL_2_3_1WEB
- https://gitlab.com/gitlab-org/gitlab/-/commit/179329b5c3c118924fb242dc449d06b4ed6ccb66WEB
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NJCJVYHPY6LNUFM6LYZIAUIYOMVT5QGVWEB
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/S3BBLUIDCUUR3NEE4NJLOCCAV3ALQ3O6WEB
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SYOLQKFL6IJCQLBXV34Z4TI4O54GESPRWEB
- https://www.debian.org/security/2021/dsa-4890WEB
Frequently Asked Questions
- What is CVE-2021-28834?
- Remote code execution in Kramdown This vulnerability has been assigned a severity rating of HIGH (CVSS score: 9.8/10).
- How do I check if my project is affected by CVE-2021-28834?
- CVE-2021-28834 affects kramdown. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2021-28834 and 200,000+ other known vulnerabilities.
Severity & Exploitability
Exploitation is straightforward and causes maximum impact. Patch immediately.
Also Known As
Related CVEs
- CVE-2020-14001CRITICAL
Unintended read access in kramdown gem
- CVE-2026-94462HIGH
Spree: Broken Access Control in `PATCH /api/v3/store/carts/:id/associate` (IDOR)
- CVE-2026-77601HIGH
OpenC3 COSMOS: Authenticated OS command injection via the `pypi_url` setting
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