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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 21 Mar 2022.
FirefoxWeb browser · Mozilla

CVE-2022-26485

HIGH · 8.8 CVSS v3.1 Published 2022-12-22
Fix available
A fix is available. Upgrade to 91.6.1 / 91.6.2 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Public exploit 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
Removing an XSLT parameter during processing could have lead to an exploitable use-after-free. We have had reports of attacks in the wild abusing this flaw. This vulnerability affects Firefox < 97.0.2, Firefox ESR < 91.6.1, Firefox for Android < 97.3.0, Thunderbird < 91.6.2, and Focus < 97.3.0.

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 use-after-free vulnerability exists in Firefox, Thunderbird, and Focus when removing XSLT parameters during processing. This memory corruption flaw can be exploited for remote code execution. In-the-wild attacks have been observed.

MitigationUpdate affected Mozilla products to version 97.0.2 (Firefox), 91.6.1 (Firefox ESR), 91.6.2 (Thunderbird), or 97.3.0 (Firefox for Android/Focus) to remediate this vulnerability.

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:< 91.6.1< 97.0.2< 97.3.0
Firefox FocusWeb browser
Affected:< 97.3.0
ThunderbirdApplication
Affected:< 91.6.2

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checks

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

  1. Identify installed Mozilla products
    Check for installed Mozilla software: look for Firefox, Thunderbird, or Firefox Focus in program directories (Windows: C:\Program Files\Mozilla Firefox, C:\Program Files\Mozilla Thunderbird; Mac: /Applications/Firefox.app, /Applications/Thunderbird.app; Linux: /usr/lib/firefox). On Android, check installed apps for Firefox Focus.
    Affected if Any of these products are installed on the system
  2. Check Firefox version number
    For Firefox desktop: open menu > Help > About Firefox, or navigate to about:support in address bar, or check version file in installation directory (firefox.dll version resource on Windows, Info.plist on Mac, firefox.ini on Linux)
    Affected if Installed version is less than 91.6.1, or falls between 91.6.1 and 97.0.1 inclusive, or falls between 97.0.2 and 97.2.x inclusive
  3. Check Thunderbird version number
    Open Thunderbird: menu > Help > About Thunderbird, or navigate to about:support, or check version in installation directory (similar paths to Firefox)
    Affected if Installed version is less than 91.6.2
  4. Check Firefox Focus version number
    On Android device: go to Play Store app page, or open Firefox Focus > tap three-dot menu > Settings > About, or check Android package manager for versionName
    Affected if Installed version is less than 97.3.0

The environment is affected if any installed Mozilla product (Firefox < 91.6.1, < 97.0.2, or < 97.3.0; Thunderbird < 91.6.2; Firefox Focus < 97.3.0) matches the vulnerable version ranges for that specific product.

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 91.6.1 / 91.6.2 / 97.0.2 or later
Fixed in 91.6.191.6.297.0.2
Interim mitigation

Update affected Mozilla products to version 97.0.2 (Firefox), 91.6.1 (Firefox ESR), 91.6.2 (Thunderbird), or 97.3.0 (Firefox for Android/Focus) to remediate this vulnerability.

Recommended fix High confidence

Firefox 97.0.2 or Firefox ESR 91.6.1 (Android: 97.3.0), Thunderbird 91.6.2, Focus 97.3.0

  1. Identify which Mozilla product is affected (Firefox, Firefox ESR, Firefox for Android, Thunderbird, or Focus)
  2. Check the current installed version (Help > About Firefox/Thunderbird or Settings in Focus)
  3. Close all instances of the application
  4. Update to the fixed version via: Help > About > Check for Updates, or download from mozilla.org
  5. Restart the application after update completes
  6. Verify the version has been updated to a fixed release
Caveat Standard Mozilla release updates; some browser extensions may require updates to remain compatible

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

Fix this in Firefox Exploited in the wild — priority engagement
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get it fixed fast

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

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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-2022-26485 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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