Email ExtensionPlugin / extension · Jenkins
CVE-2026-48920
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedJenkins 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceJenkins Email Extension Plugin versions 1933.v45cec755423f and earlier allows inlining images as base64 via the 'data-inline' attribute without validating URL schemes, enabling attackers with control over email content to use 'file:' URLs to read arbitrary files from the Jenkins controller filesystem.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Email ExtensionPlugin / extension
<= 1925.v1598902b_58dd= 1933.v45cec755423fCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Email Extension Plugin versionNavigate to Manage Jenkins > Manage Plugins > Installed tab and search for 'Email Extension' or check the version in the plugin's MANIFEST.MF file in the jenkins/plugins/email-ext directoryAffected if The installed version is 1933.v45cec755423f or earlier, or version 1925.v1598902b_58dd or earlier (these are the affected versions)
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Identify email templates using data-inlineSearch Jenkins job configurations and any custom email templates for the string 'data-inline' - inspect email-templates/ directory and job config.xml filesAffected if Templates contain 'data-inline' attribute with image sources that could be controlled by users
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Audit user access to email contentReview who has permission to configure jobs with email notifications, check if anonymous or untrusted users can modify email templates or triggersAffected if Users with job configuration permissions or ability to inject content into email templates exist in the environment
You are affected if the Email Extension Plugin version is 1933.v45cec755423f or earlier AND users with the ability to control email content (via job configs or templates) exist in your Jenkins environment, particularly if data-inline is used.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade to Email Extension Plugin version 1934 or later which restricts URL schemes. Additionally, limit which users can control email content and consider network isolation for the Jenkins controller.
Fix this in Email Extension
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-48920 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-48920 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data