ThunderbirdApplication · Mozilla

CVE-2018-18513

HIGH · 7.5 CVSS v3.0 Published 2019-04-26
Fix available
A fix is available. Upgrade to 60.5.0 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A crash can occur when processing a crafted S/MIME message or an XPI package containing a crafted signature. This can be used as a denial-of-service (DOS) attack because Thunderbird reopens the last seen message on restart, triggering the crash again. This vulnerability affects Thunderbird < 60.5.

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 confidence

A vulnerability in Thunderbird versions before 60.5 allows specially crafted S/MIME messages or XPI packages containing malformed signatures to trigger a crash. Because Thunderbird automatically reopens the last viewed message on restart, this creates a persistent denial-of-service condition.

MitigationUpgrade Thunderbird to version 60.5 or later to obtain the patched version of the NSS library that properly handles malformed signature data.

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
ThunderbirdApplication
Affected:< 60.5.0

CVSS 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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Thunderbird version
    Open Thunderbird, go to Help > About Thunderbird, or run 'thunderbird --version' from command line
    Affected if Version is below 60.5.0 (e.g., 60.4.0, 60.3.0, etc.)
  2. Verify S/MIME configuration
    Go to Account Settings > End-to-End Encryption in Thunderbird, check if S/MIME is enabled for any accounts
    Affected if S/MIME is enabled and the installed version is vulnerable
  3. Check for recent crashes
    Look in Thunderbird's crash reports at about:crashes or the profiles directory for .txt crash report files matching the timeframe of opening S/MIME messages
    Affected if Crashes occurred after viewing S/MIME messages with the vulnerable version
  4. Inspect profile for last viewed message
    Check the prefs.js file in the profile folder for 'mailnews.scrollbar' or last message metadata that may indicate a message that triggered the crash on restart
    Affected if The last opened message was an S/MIME signed message and Thunderbird crashes on restart

User is affected if Thunderbird version is below 60.5.0 and S/MIME signed messages or XPI packages have been opened, resulting in persistent crashes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 60.5.0 or later
Fixed in 60.5.0
Interim mitigation

Upgrade Thunderbird to version 60.5 or later to obtain the patched version of the NSS library that properly handles malformed signature data.

Fix this in Thunderbird Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-18513 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-18513 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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