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FirefoxWeb browser · Mozilla

CVE-2025-1934

MEDIUM · 6.5 CVSS v3.1 Published 2025-03-04
Fix available
A fix is available. Upgrade to 128.8.0 / 136.0 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

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
It was possible to interrupt the processing of a RegExp bailout and run additional JavaScript, potentially triggering garbage collection when the engine was not expecting it. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

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 the SpiderMonkey JavaScript engine allows interruption of RegExp bailout processing to run additional JavaScript code, potentially triggering garbage collection at unexpected times. This could lead to memory corruption and potentially enable arbitrary code execution.

MitigationUpdate affected software to the fixed versions: Firefox 136+, Firefox ESR 128.8+, Thunderbird 136+, or Thunderbird 128.8+.

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
Affected:< 128.8.0< 136.0
ThunderbirdApplication
Affected:< 128.8.0>= 129.0, < 136.0

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
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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. Identify installed Mozilla product
    Check if Firefox or Thunderbird is installed. On Windows check Program Files for Mozilla Firefox or Mozilla Thunderbird folders. On macOS check /Applications for Firefox.app or Thunderbird.app. On Linux check package manager or look in /usr/lib/firefox or /usr/lib/thunderbird.
    Affected if Either Firefox or Thunderbird is installed
  2. Determine Firefox version
    For Firefox: Click menu > Help > About Firefox, or navigate to about:support in the address bar, or run 'firefox --version' from command line.
    Affected if Version is shown as less than 128.8.0 or less than 136.0 (any version between 129.0 and 135.9 is also affected)
  3. Determine Thunderbird version
    For Thunderbird: Click menu > Help > About Thunderbird, or run 'thunderbird --version' from command line.
    Affected if Version is shown as less than 128.8.0 or between 129.0 and 135.9 inclusive
  4. Confirm SpiderMonkey engine is present
    SpiderMonkey is the JavaScript engine embedded in Firefox and Thunderbird. Its presence is inherent to these products - no additional installation or configuration needed.
    Affected if The product is a vulnerable version of Firefox or Thunderbird as determined above

You are affected if you have Firefox or Thunderbird installed with a version less than 128.8.0, or any version from 129.0 through 135.9.

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.

dbcve · scoped
Upgrade available Upgrade to 128.8.0 / 136.0 or later
Fixed in 128.8.0136.0
Interim mitigation

Update affected software to the fixed versions: Firefox 136+, Firefox ESR 128.8+, Thunderbird 136+, or Thunderbird 128.8+.

Recommended fix High confidence

Firefox 136 (or Firefox ESR 128.8); Thunderbird 136 (or Thunderbird 128.8)

  1. Check current Firefox version by navigating to Menu > Help > About Firefox
  2. Check current Thunderbird version by navigating to Menu > Help > About Thunderbird
  3. For Firefox: Upgrade to version 128.8.0 or 136.0 (or later) via Menu > Help > About Firefox > Restart to update
  4. For Thunderbird: Upgrade to version 128.8.0 or 136.0 (or later) via Menu > Help > About Thunderbird > Restart to update
  5. On enterprise deployments, update via system package manager or centralized software deployment tools to version Firefox ESR 128.8 or Thunderbird 128.8

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
3.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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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-2025-1934 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