CVE-2021-21603
CVE-2021-21603 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:
- Last modified:
Description
Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape notification bar response contents, resulting in a cross-site scripting (XSS) vulnerability.
Frequently asked questions
- What is CVE-2021-21603?
- Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape notification bar response contents, resulting in a cross-site scripting (XSS) vulnerability.
- How severe is CVE-2021-21603?
- CVE-2021-21603 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-2021-21603 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-2021-21603?
- CVE-2021-21603 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-2021-21603?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-21603 published?
- CVE-2021-21603 was published on 2021-01-13 and last updated on 2026-06-17.
References
Affected products (2)
- cpe:2.3:a:jenkins:jenkins:*:*:*:*:lts:*:*:*
- cpe:2.3:a:jenkins:jenkins:*:*:*:*:-:*:*:*
More vulnerabilities in Jenkins
- CVE-2024-23897 — Critical (CVSS 9.8): Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable a feature of its CLI command parser that replaces…
- CVE-2021-21696 — Critical (CVSS 9.8): Jenkins 2.318 and earlier, LTS 2.303.2 and earlier does not limit agent read/write access to the libs/ directory inside…
- CVE-2021-21694 — Critical (CVSS 9.8): FilePath#toURI, FilePath#hasSymlink, FilePath#absolutize, FilePath#isDescendant, and FilePath#get*DiskSpace do not…
- CVE-2021-21693 — Critical (CVSS 9.8): When creating temporary files, agent-to-controller access to create those files is only checked after they've been…
- CVE-2021-21692 — Critical (CVSS 9.8): FilePath#renameTo and FilePath#moveAllChildrenTo in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier only check…
- CVE-2021-21691 — Critical (CVSS 9.8): Creating symbolic links is possible without the 'symlink' agent-to-controller access control permission in Jenkins…
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