How severe is CVE-2021-21658?

CVE-2021-21658 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-21658 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21658?

CVE-2021-21658 affects Jenkins Nuget. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21658?

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

When was CVE-2021-21658 published?

CVE-2021-21658 was published on 2021-05-25 and last updated on 2026-06-17.

CVE-2021-21658

CVE-2021-21658 is a critical-severity vulnerability in Jenkins Nuget with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Jenkins Nuget
Published: 2021-05-25
Last modified: 2026-06-17

Description

Jenkins Nuget Plugin 1.0 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

Frequently asked questions

What is CVE-2021-21658?: Jenkins Nuget Plugin 1.0 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.
How severe is CVE-2021-21658?: CVE-2021-21658 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-21658 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21658?: CVE-2021-21658 affects Jenkins Nuget. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21658?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-21658 published?: CVE-2021-21658 was published on 2021-05-25 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:jenkins:nuget:*:*:*:*:*:jenkins:*:*