How severe is CVE-2021-28833?

CVE-2021-28833 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-28833 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28833?

CVE-2021-28833 affects Increments Qiita. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28833?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-28833 published?

CVE-2021-28833 was published on 2021-06-21 and last updated on 2026-06-17.

CVE-2021-28833

CVE-2021-28833 is a medium-severity vulnerability in Increments Qiita with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Increments Qiita
Published: 2021-06-21
Last modified: 2026-06-17

Description

Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.

Frequently asked questions

What is CVE-2021-28833?: Increments Qiita::Markdown before 0.34.0 allows XSS via a crafted gist link, a different vulnerability than CVE-2021-28796.
How severe is CVE-2021-28833?: CVE-2021-28833 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-28833 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28833?: CVE-2021-28833 affects Increments Qiita. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28833?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-28833 published?: CVE-2021-28833 was published on 2021-06-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:increments:qiita\:\:markdown:*:*:*:*:*:*:*:*

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