How severe is CVE-2021-21656?

CVE-2021-21656 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2021-21656 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21656?

CVE-2021-21656 affects Jenkins Xcode Integration. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21656?

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-2021-21656 published?

CVE-2021-21656 was published on 2021-05-11 and last updated on 2026-06-17.

CVE-2021-21656

CVE-2021-21656 is a high-severity vulnerability in Jenkins Xcode Integration with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 5.5
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Jenkins Xcode Integration
Published: 2021-05-11
Last modified: 2026-06-17

Description

Jenkins Xcode integration Plugin 2.0.14 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

Frequently asked questions

What is CVE-2021-21656?: Jenkins Xcode integration Plugin 2.0.14 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.
How severe is CVE-2021-21656?: CVE-2021-21656 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2021-21656 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21656?: CVE-2021-21656 affects Jenkins Xcode Integration. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21656?: 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-2021-21656 published?: CVE-2021-21656 was published on 2021-05-11 and last updated on 2026-06-17.

References

https://www.jenkins.io/security/advisory/2021-05-11/#SECURITY-2335

Affected products (1)

cpe:2.3:a:jenkins:xcode_integration:*:*:*:*:*:jenkins:*:*