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CVE-2021-21610

CVE-2021-21610: Reflected XSS vulnerability in Jenkins markup formatter preview

6.1

CVSS Score
3.1

Basic Information

CVE ID
CVE-2021-21610
GHSA ID
GHSA-7qf3-c2q8-69m3
EPSS Score
0.53648%
CWE
CWE-79
Published
5/24/2022
Updated
12/14/2023
KEV Status
No
Technology
TechnologyJava

Technical Details

CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Package NameEcosystemVulnerable VersionsFirst Patched Version
org.jenkins-ci.main:jenkins-coremaven<= 2.263.12.263.2
org.jenkins-ci.main:jenkins-coremaven>= 2.264, <= 2.2742.275

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability stems from the preview endpoint accepting GET requests and lacking security headers. The commit shows the patched version adds @POST annotation to doPreviewDescription and introduces CSP headers, while adding a separate GET handler that blocks unsafe access. In vulnerable versions, the original doPreviewDescription method was accessible via GET requests without security headers, making it the entry point for XSS payloads when combined with unsafe markup formatters.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

J*nkins *llows **ministr*tors to **oos* t** m*rkup *orm*tt*r to us* *or **s*riptions o* jo*s, *uil*s, vi*ws, *t*. *ispl*y** in J*nkins. W**n **itin* su** * **s*ription, us*rs **n **oos* to **v* J*nkins r*n**r * *orm*tt** pr*vi*w o* t** **s*ription t*

Reasoning

T** vuln*r**ility st*ms *rom t** pr*vi*w *n*point ****ptin* **T r*qu*sts *n* l**kin* s**urity *****rs. T** *ommit s*ows t** p*t**** v*rsion ***s @POST *nnot*tion to *oPr*vi*w**s*ription *n* intro*u**s *SP *****rs, w*il* ***in* * s*p*r*t* **T **n*l*r