CVE-2021-28833
qiita-markdown Cross-site Scripting vulnerability
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
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
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
- Record
CVE-2021-28833- 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
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
- Record
CVE-2021-28833- Updated
- 2026-11-02
EUVDEUVD-2021-1664 No score
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
- Record
EUVD-2021-1664- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-9p29-94hp-8rvc
qiita-markdown Cross-site Scripting vulnerability
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
- Record
GHSA-9p29-94hp-8rvc- 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
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
- Record
CVE-2021-28833- 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-9p29-94hp-8rvc
qiita-markdown Cross-site Scripting vulnerability
Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
- Record
GHSA-9p29-94hp-8rvc- 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
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
qiita-markdownRubyGems |
before 0.34.0 | 0.34.0 |
qiita-markdownRubyGems |
before 0.34.0, plus listed versions 0.0.10.0.20.0.30.0.40.0.5 Show 45 moreShow less0.0.60.0.70.0.80.0.90.1.00.1.10.1.20.1.30.1.40.1.50.1.60.1.70.1.80.1.90.10.00.11.00.11.10.11.20.11.30.11.40.11.50.12.00.13.00.14.00.15.00.16.00.16.10.16.20.17.00.18.00.19.00.19.10.2.00.2.10.2.20.20.00.20.10.21.00.22.00.23.00.24.00.25.00.26.00.27.00.28.0 |
0.34.0 |
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-2021-28833 is a medium vulnerability (CVSS 6.1) in Increments Qiita\, published June 21, 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 qiita-markdown 0.34.0.
References
github.com/increments/qiita-markdown/releases
vuln.ryotak.me/advisories/50
nvd.nist.gov/vuln/detail/CVE-2021-28833
Left out here: 16 versions. The JSON record has them.