How severe is CVE-2021-21611?

CVE-2021-21611 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-21611 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21611?

CVE-2021-21611 primarily affects Jenkins. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21611?

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

When was CVE-2021-21611 published?

CVE-2021-21611 was published on 2021-01-13 and last updated on 2026-06-17.

CVE-2021-21611

CVE-2021-21611 is a medium-severity vulnerability in Jenkins with a CVSS 3.x base score of 5.4. 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 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Jenkins
Published: 2021-01-13
Last modified: 2026-06-17

Description

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape display names and IDs of item types shown on the New Item page, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to specify display names or IDs of item types.

Frequently asked questions

What is CVE-2021-21611?: Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape display names and IDs of item types shown on the New Item page, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers able to specify display names or IDs of item types.
How severe is CVE-2021-21611?: CVE-2021-21611 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-21611 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21611?: CVE-2021-21611 primarily affects Jenkins. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21611?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21611 published?: CVE-2021-21611 was published on 2021-01-13 and last updated on 2026-06-17.

References

https://www.jenkins.io/security/advisory/2021-01-13/#SECURITY-2171

Affected products (2)

cpe:2.3:a:jenkins:jenkins:*:*:*:*:lts:*:*:*
cpe:2.3:a:jenkins:jenkins:*:*:*:*:-:*:*:*

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