Jenkins Email Extension Plugin: Attackers able to control email content may specify `file:` URLs for images to read arbitrary files from Jenkins controller filesystem

published 2026-05-27 5 mo ago modified 2026-10-14 25 d ago also GHSA-mq58-m26g-46gp , EUVD-2026-32511

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits: 0; none known

Jenkins Email Extension Plugin 1933.v45cec755423f and earlier allows inlining images as `base64` in email content by setting the `data-inline` attribute, without restrictions on the image URLs that can be inlined, allowing attackers able to control the email content to specify `file:` URLs for images to read arbitrary files from the Jenkins controller filesystem.

Patch / fix

fixed in 1

maven org.jenkins-ci.plugins:email-ext 1933.1935.v276319e3cc47

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-48920 updated 2026-06-28 cvss 5.5

jenkins-email-extension-plugin: Jenkins Email Extension Plugin: Information disclosure via arbitrary file read

Red Hat OpenShift Developer Tools and Services jenkins-2-plugins, ocp-tools-4/jenkins-rhel8, ocp-tools-4/jenkins-rhel9
affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 5 mo ago (2026-05-27)

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
GitHub	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
maven	org.jenkins-ci.plugins:email-ext	<1933.1935.v276319e3cc47	1933.1935.v276319e3cc47

Affected products

Jenkins Project Jenkins Email Extension Plugin

Classification

Weakness

CWE-73 External Control of File Name or Path

References

jenkins.io /security/advisory/2026-05-27/#SECURITY-3705
vendor-advisory, web
nvd.nist.gov /vuln/detail/CVE-2026-48920
advisory
github.com /jenkinsci/email-ext-plugin
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary