FirefoxWeb browser · Mozilla
CVE-2025-8032
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 · uneditedXSLT document loading did not correctly propagate the source document which bypassed its CSP. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
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 confidenceXSLT document loading in Firefox and Thunderbird failed to propagate the source document's Content Security Policy (CSP), allowing attackers to bypass CSP protections. This client-side vulnerability enables potentially malicious scripts to execute without CSP restrictions when processing XSLT-transformed content.
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
FirefoxWeb browser
< 128.13.0< 141.0>= 140.0, < 140.1.0< 128.13.0< 141.0>= 140.0, < 140.1.0CVSS 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
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 Firefox version on WindowsOpen Firefox, click the menu button (three horizontal lines), select Help, then 'About Firefox'. The version number is displayed in the window that opens.Affected if The version shown is less than 128.13.0, or 140.0.x (where x is less than 1.0.0), or any version from 141.0.0 up to but not including 141.0.0 (no versions in this range are affected) - effectively: < 128.13.0, 140.0.x (< 140.1.0), or 140.1.0 is not yet released so the only vulnerable ranges are < 12
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Check Firefox version on macOSOpen Firefox, click the Firefox menu in the menu bar, then select 'About Firefox'. The version number appears in the dialog.Affected if Same version conditions as Windows check apply - version is < 128.13.0 or 140.0.x where x < 1.0.0
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Check Thunderbird version on WindowsOpen Thunderbird, click the menu button (three horizontal lines), select Help, then 'About Thunderbird'. The version number is displayed in the window that opens.Affected if Version is < 128.13.0 or between 140.0.0 and 140.0.x where x < 1.0.0
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Check Thunderbird version on macOSOpen Thunderbird, click the Thunderbird menu in the menu bar, then select 'About Thunderbird'. The version number appears in the dialog.Affected if Same version conditions as Windows check apply - version is < 128.13.0 or 140.0.x < 140.1.0
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Determine if XSLT processing is in useThe vulnerability applies when processing XSLT-transformed XML content. This is a built-in browser/mail client capability triggered when loading XML documents that reference an XSLT stylesheet via an xml-stylesheet processing instruction. No user-configurable setting controls this - it is handled internally when such documents are loaded.Affected if The browser or mail client processes any XSLT-styled XML content while running an affected version, which can allow script execution to bypass Content Security Policy restrictions.
A user is affected if they have Firefox or Thunderbird installed with a version less than 128.13.0 or between 140.0.0 and 140.0.x (where x < 1.0.0), and the application processes XSLT-transformed content.
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 · scoped128.13.0140.1.0141.0
Update affected software to Firefox 141+, Firefox ESR 128.13+/140.1+, or Thunderbird 141+/128.13+/140.1+ to apply the security fix.
Firefox 141.0+ (standard) or Firefox ESR 128.13.0+/140.1.0+; Thunderbird 141.0+ (standard) or Thunderbird ESR 128.13.0+/140.1.0+
- 1. Check current Firefox or Thunderbird version via Help > About (or 'firefox --version' / 'thunderbird --version' in terminal
- 2. Determine which release track is in use: standard Firefox/Thunderbird (rapid) or Firefox ESR/Thunderbird ESR
- 3. For standard Firefox: upgrade to version 141.0 or later
- 4. For Firefox ESR: upgrade to version 128.13.0 or later, OR version 140.1.0 or later
- 5. For standard Thunderbird: upgrade to version 141.0 or later
- 6. For Thunderbird ESR: upgrade to version 128.13.0 or later, OR version 140.1.0 or later
- 7. Restart the application and verify version via Help > About
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 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 $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-8032 — 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-2025-8032 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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- Version or environment caveats, and links to real fixes
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