CVE-2021-21603: jenkins project jenkins
Vulnerability summary
CVE-2021-21603 is a medium (CVSS 5.4) vulnerability in jenkins project jenkins. EPSS estimates a 1.04% chance of exploitation in the next 30 days, higher than 64% of scored vulnerabilities.
Not severe (CVSS 5.4, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 4Timeline
- 13-01-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · MavenEcosystem advisory · calculated5.4MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- OSV · AlpineEcosystem advisory · calculated5.4MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS trend
Probability
1.04%
Chance of exploitation in the next 30 days
Percentile
64%
Versus all other CVEs
30-day change
Increase +0.01 pp
From 1.03% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, user interaction (CVSS vector). Other conditions: not stated in public data.
Alpine1 product
- jenkins< 2.275-r0
Jenkins1 product
- jenkins≤ 2.263.1 | ≤ 2.274
Jenkins project1 product
- jenkins≥ unspecified, ≤ 2.274 | ≥ unspecified, ≤ LTS 2.263.1
Org.jenkins-ci.main1 product
- jenkins-core< 2.275 | ≥ 2.263.2, < 2.275
4 vendors · 4 products
References
5 links
- github.com/jenkinsci/jenkinsPACKAGE