CVE-2021-28834
CRITICALCVSS 9.8/10EPSS 2.82%
Last modified
CVE-2021-28834 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.. EPSS estimates a 2.82% chance of exploitation in the next 30 days.
Description
Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Kramdown Project | Kramdown | < 2.3.1 |
| Fedoraproject | Fedora | 32 |
| Fedoraproject | Fedora | 33 |
| Fedoraproject | Fedora | 34 |
| Debian | Debian Linux | 10.0 |
References
- https://github.com/gettalong/kramdown/compare/REL_2_3_0...REL_2_3_1Patch, Third Party Advisory
- https://github.com/gettalong/kramdown/pull/708Exploit, Third Party Advisory
- https://gitlab.com/gitlab-org/gitlab/-/commit/179329b5c3c118924fb242dc449d06b4ed6ccb66Patch, Third Party Advisory
- https://www.debian.org/security/2021/dsa-4890Third Party Advisory
- https://github.com/gettalong/kramdown/compare/REL_2_3_0...REL_2_3_1Patch, Third Party Advisory
- https://github.com/gettalong/kramdown/pull/708Exploit, Third Party Advisory
- https://gitlab.com/gitlab-org/gitlab/-/commit/179329b5c3c118924fb242dc449d06b4ed6ccb66Patch, Third Party Advisory
- https://www.debian.org/security/2021/dsa-4890Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-28834?
Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.
How severe is CVE-2021-28834?
CVE-2021-28834 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.82% probability of exploitation in the next 30 days.
How do I fix CVE-2021-28834?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2021
- CVE-2021-28828The Administration GUI component of TIBCO Software Inc.'s TI…8.8
- CVE-2021-28829The Administration GUI component of TIBCO Software Inc.'s TI…8
- CVE-2021-28830The TIBCO Spotfire Server and TIBCO Enterprise Runtime for R…7.8
- CVE-2021-28831decompress_gunzip.c in BusyBox through 1.32.1 mishandles the…7.5
- CVE-2021-28832VSCodeVim before 1.19.0 allows attackers to execute arbitrar…7.8
- CVE-2021-28833Increments Qiita::Markdown before 0.34.0 allows XSS via a cr…6.1
- CVE-2021-28835Buffer Overflow vulnerability in XNView before 2.50, allows …7.8
- CVE-2021-28838Null pointer dereference vulnerability in D-Link DAP-2310 2,…7.5
- CVE-2021-28839Null Pointer Dereference vulnerability exists in D-Link DAP-…7.5
- CVE-2021-28840Null Pointer Dereference vulnerability exists in D-Link DAP-…7.5
- CVE-2021-28841Null Pointer Dereference vulnerability in TRENDnet TEW-755AP…7.5
- CVE-2021-28842Null Pointer Deference vulnerability exists in TRENDnet TEW-…7.5
Are you affected by CVE-2021-28834?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST