How severe is CVE-2021-21604?

CVE-2021-21604 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-21604 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21604?

CVE-2021-21604 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-2021-21604?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-21604 published?

CVE-2021-21604 was published on 2021-01-13 and last updated on 2026-06-17.

CVE-2021-21604

CVE-2021-21604 is a high-severity vulnerability in Jenkins with a CVSS 3.x base score of 8.0. 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-502.

Key facts

Severity: High (CVSS 3.x base score 8.0)
CVSS v2: 6.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Jenkins
Published: 2021-01-13
Last modified: 2026-06-17

Description

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows attackers with permission to create or configure various objects to inject crafted content into Old Data Monitor that results in the instantiation of potentially unsafe objects once discarded by an administrator.

Frequently asked questions

What is CVE-2021-21604?: Jenkins 2.274 and earlier, LTS 2.263.1 and earlier allows attackers with permission to create or configure various objects to inject crafted content into Old Data Monitor that results in the instantiation of potentially unsafe objects once discarded by an administrator.
How severe is CVE-2021-21604?: CVE-2021-21604 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-21604 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21604?: CVE-2021-21604 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-2021-21604?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-21604 published?: CVE-2021-21604 was published on 2021-01-13 and last updated on 2026-06-17.

References

https://www.jenkins.io/security/advisory/2021-01-13/#SECURITY-1923

Affected products (2)

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

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