CVE-2026-48920: Jenkins Email Extension Plugin Attackers Able To Control Email Vulnerability

HIGH
Advisory Identifier: GHSA-mq58-m26g-46gp
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CVSS 8.8
CWE-73
Published
Advisory Summary

CVE-2026-48920 is a HIGH (CVSS 8.8) attackers able to control email vulnerability (CWE-73: External Control of File Name or Path) affecting Jenkins Email Extension Plugin libraries in the Maven ecosystem. The issue involves attackers able to control email content may specify `file:` urls for images to read arbitrary files from jenkins controller filesystem. Remediation is available by upgrading affected packages to version 1933.1935.v276319e3cc47.

CVE-2026-48920 at a Glance

CVE Identifier CVE-2026-48920
GHSA Identifier GHSA-mq58-m26g-46gp
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-73: External Control of File Name or Path
Affected Product Jenkins Email Extension Plugin
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-48920

To remediate this vulnerability, upgrade all affected Jenkins Email Extension Plugin dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.jenkins-ci.plugins:email-ext fixed: 1933.1935.v276319e3cc47 
<dependency>
    <groupId>org.jenkins-ci.plugins</groupId>
    <artifactId>email-ext</artifactId>
    <version>1933.1935.v276319e3cc47</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-48920, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.jenkins-ci.plugins

Analyze the terminal output to locate any version of Jenkins Email Extension Plugin in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1933.1935.v276319e3cc47), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.jenkins-ci.plugins command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-73: External Control of File Name or Path, where the product allows user input to control or influence paths or file names that are used in filesystem operations. In Jenkins Email Extension Plugin, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Jenkins Email Extension Plugin 1933.v45cec755423f and earlier includes a feature that allows inlining images as `base64` in email content by setting the `data-inline` attribute. No restrictions are placed on the image URLs that can be inlined. This allows attackers able to control the email content to specify `file:` URLs for images to read arbitrary files from the Jenkins controller filesystem. The feature allowing inlining images as `base64` in email content by setting the `data-inline` attribute is removed from Email Extension Plugin 1933.1935.v276319e3cc47.

CVE-2026-48920 Affected Jenkins Email Extension Plugin Versions

1 component(s)
Fixed Versions:
1933.1935.v276319e3cc47
Product / Package Ecosystem Affected Versions Fixed Version
org.jenkins-ci.plugins:email-ext
maven/org.jenkins-ci.plugins/email-ext
Maven
< 1933.1935.v276319e3cc47
1933.1935.v276319e3cc47

References

NVD — CVE-2026-48920 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-48920
Jenkins Email Extension Plugin Source Repository REPOSITORY
https://github.com/jenkinsci/email-ext-plugin
Jenkins Email Extension Plugin Security Information SECURITY
https://www.jenkins.io/security/advisory/2026-05-27/#SECURITY-3705

Frequently Asked Questions

What is CVE-2026-48920?
CVE-2026-48920 is a security vulnerability in Jenkins Email Extension Plugin involving Attackers able to control email content may specify `file:` URLs for images to read arbitrary files from Jenkins controller filesystem under CWE-73: External Control of File Name or Path.
Which Jenkins Email Extension Plugin versions are affected?
Affected versions include releases prior to 1933.1935.v276319e3cc47 across affected packages: org.jenkins-ci.plugins:email-ext.
What version fixes CVE-2026-48920?
Upgrading to 1933.1935.v276319e3cc47 (or the latest patched release for your respective branch) resolves the vulnerability.
Is email-ext affected?
Yes, org.jenkins-ci.plugins:email-ext is affected in releases prior to 1933.1935.v276319e3cc47. Upgrade your dependency to 1933.1935.v276319e3cc47 or later.
What is the CVSS score of CVE-2026-48920?
CVE-2026-48920 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-48920?
CVE-2026-48920 is classified under CWE-73: External Control of File Name or Path (The product allows user input to control or influence paths or file names that are used in filesystem operations.).
How can I check Maven dependencies for CVE-2026-48920?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.jenkins-ci.plugins'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mq58-m26g-46gp",
  "modified" : "2026-07-01T19:42:14Z",
  "published" : "2026-05-27T15:33:26Z",
  "aliases" : [ "CVE-2026-48920" ],
  "summary" : "Jenkins Email Extension Plugin: Attackers able to control email content may specify `file:` URLs for images to read arbitrary files from Jenkins controller filesystem",
  "details" : "Jenkins Email Extension Plugin 1933.v45cec755423f and earlier includes a feature that allows inlining images as `base64` in email content by setting the `data-inline` attribute. No restrictions are placed on the image URLs that can be inlined.\n\nThis allows attackers able to control the email content to specify `file:` URLs for images to read arbitrary files from the Jenkins controller filesystem.\n\nThe feature allowing inlining images as `base64` in email content by setting the `data-inline` attribute is removed from Email Extension Plugin 1933.1935.v276319e3cc47.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.jenkins-ci.plugins:email-ext"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1933.1935.v276319e3cc47"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-48920"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jenkinsci/email-ext-plugin"
  }, {
    "type" : "WEB",
    "url" : "https://www.jenkins.io/security/advisory/2026-05-27/#SECURITY-3705"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-73" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-01T19:42:14Z",
    "nvd_published_at" : "2026-05-27T15:16:31Z"
  }
}