CVE-2026-2783: Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component

Published Feb 24, 2026
·
Updated

Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 148 and Firefox ESR < 140.8.

Other sources

Information disclosure due to JIT miscompilation in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

— MITRE

Affected Software

18 affected componentsFixes available
Mozilla Thunderbird<148
148
Mozilla Thunderbird<140.8
140.8
Mozilla Firefox<140.8.0
Mozilla Firefox<148.0
Mozilla Thunderbird<140.8.0
Mozilla Thunderbird<148.0
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird*
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<148
148
Mozilla Firefox ESR<140.8
140.8

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 148
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 140.8
  3. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 148
  4. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.8
  5. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 148
  6. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.8

Event History

Feb 24, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
CVE Published
via MITRE·01:33 PM
Data Sourced
via MITRE·01:33 PM
Description
Data Sourced
via Red Hat·02:03 PM
DescriptionSeverityAffected Software
Data Sourced
via OSV·02:16 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:16 PM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What is the severity of CVE-2026-2783?

The severity of CVE-2026-2783 is considered moderate due to potential information disclosure risks.

2

How do I fix CVE-2026-2783?

To fix CVE-2026-2783, update to Mozilla Firefox version 148 or Mozilla Firefox ESR version 140.8 or higher.

3

Which versions of Firefox are affected by CVE-2026-2783?

CVE-2026-2783 affects Firefox versions lower than 148 and Firefox ESR versions lower than 140.8.

4

What type of vulnerability is CVE-2026-2783?

CVE-2026-2783 is an information disclosure vulnerability resulting from JIT miscompilation in the JavaScript Engine.

5

Is CVE-2026-2783 specific to certain platforms?

CVE-2026-2783 is specific to the Firefox and Firefox ESR browsers on various platforms.

Company

Resources

Contact

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