CVE-2025-1015
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 · uneditedThe Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.
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 confidenceThunderbird's Address Book URI fields contained unsanitized links, allowing attackers to embed malicious payloads in fields such as the 'Other' field of the Instant Messaging section. When a victim imported a crafted address book and clicked the link, it opened within Thunderbird's internal browser context, enabling unprivileged JavaScript execution - effectively a stored XSS vulnerability via address book import/export.
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>= 128.0.1, < 128.7.0CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
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 installed Thunderbird versionNavigate to Thunderbird > About Thunderbird (or run thunderbird --version from command line). Compare the version number to the affected range: 128.0.1 through 128.6.xAffected if Version falls within 128.0.1 <= version < 128.7.0
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Locate Thunderbird profile directoryCheck default profile locations: On Windows: %APPDATA%\Thunderbird\Profiles\; On macOS: ~/Library/Thunderbird/Profiles/; On Linux: ~/.thunderbird/Affected if Profile directory exists and contains address book files ( .mab or .ab files)
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Identify imported address booksReview the profile's abook.mab and history.mab files, or check the Address Book sidebar for entries with populated Instant Messaging 'Other' fields containing URLsAffected if Address books contain entries with URL links in URI/Other fields that were imported from external sources
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Inspect address book import behaviorAttempt a test import of a crafted LDIF or vCard file containing a URL in the Instant Messaging Other field, then click the link to verify it opens in Thunderbird's internal browserAffected if Links in address book fields render and execute within Thunderbird's internal browser context rather than being sanitized or blocked
A user is affected if Thunderbird version is between 128.0.1 and 128.6.x inclusive AND they have imported address books containing links in URI fields from potentially untrusted sources.
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.
dbcve · scoped128.7.0
Upgrade Thunderbird to version 128.7, 135, or later. Avoid importing address books from untrusted or unknown sources until patching is complete.
Thunderbird 128.7 or Thunderbird 135
- Check current Thunderbird version via Help > About Thunderbird or running 'thunderbird --version' in terminal
- Navigate to https://www.thunderbird.net/ and download Thunderbird 128.7 (or latest Thunderbird 135) for your operating system
- Run the installer and follow the prompts to upgrade Thunderbird
- After installation, verify the version by checking Help > About Thunderbird shows version 128.7 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-1015 — 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-2025-1015 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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- 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
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