CVE-2021-28796

Cross-Site Scripting in Qiita-Markdown

6.1 MediumFix available

Increments Qiita::Markdown before 0.33.0 allows XSS in transformers.

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

0.77%Up 0.2 points since Apr 14, 2021

What each source reports

NVD Score used 6.1

Increments Qiita::Markdown before 0.33.0 allows XSS in transformers.

Record: CVE-2021-28796
CVSS 3.1: 6.1 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS 2.0: 4.3 MediumAV: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 0.33.0 allows XSS in transformers.

Record: CVE-2021-28796
Updated: 2026-11-02

EUVDEUVD-2021-1689 No score

Increments Qiita::Markdown before 0.33.0 allows XSS in transformers.

Record: EUVD-2021-1689
Updated: 2026-11-03

GitHub AdvisoriesGHSA-f2c9-5jqw-3xh3 6.1

Cross-Site Scripting in Qiita-Markdown

Increments Qiita-Markdown before 0.33.0 allows XSS in transformers.

Record: GHSA-f2c9-5jqw-3xh3
CVSS 3.1: 6.1 MediumCVSS: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 6.1

Increments Qiita::Markdown before 0.33.0 allows XSS in transformers.

Record: CVE-2021-28796
CVSS 3.1: 6.1 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Updated: 2026-11-02

OSVGHSA-f2c9-5jqw-3xh3 6.1

Cross-Site Scripting in Qiita-Markdown

Increments Qiita-Markdown before 0.33.0 allows XSS in transformers.

Record: GHSA-f2c9-5jqw-3xh3
CVSS 3.1: 6.1 MediumCVSS: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

increments qiita\

Affected packages

Affected packages
Package	Affected	Fixed
`qiita-markdown` RubyGems	before 0.33.0	0.33.0
`qiita-markdown` RubyGems	before 0.33.0, plus listed versions 0.0.10.0.20.0.30.0.40.0.5 Show 45 moreShow less 0.0.60.0.70.0.80.0.90.1.00.1.10.1.20.1.30.1.40.1.50.1.60.1.70.1.80.1.90.10.00.11.00.11.10.11.20.11.30.11.40.11.50.12.00.13.00.14.00.15.00.16.00.16.10.16.20.17.00.18.00.19.00.19.10.2.00.2.10.2.20.20.00.20.10.21.00.22.00.23.00.24.00.25.00.26.00.27.00.28.0	0.33.0

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-28796 is a medium vulnerability (CVSS 6.1) in Increments Qiita\, published March 18, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.77%, the 55th percentile. Fixed in qiita-markdown 0.33.0.

References

This page doesn't list everything

Left out here: 15 versions. The JSON record has them.