CVE-2025-4083: Process isolation bypass using "javascript:" URI links in cross-origin frames

Published Apr 29, 2025
·
Updated

A process isolation vulnerability in Firefox stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape.

Other sources

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

— Ubuntu

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document’s process instead of the intended frame, potentially enabling a sandbox escape.

— Mozilla

Affected Software

27 affected componentsFixes available
Mozilla Firefox<138
Mozilla Firefox ESR<128.10, <115.23
Mozilla Thunderbird<138, <128.10
Mozilla Thunderbird ESR<128.10
Mozilla Thunderbird<138
138
Mozilla Firefox ESR<115.23
115.23
Mozilla Firefox<115.23
Mozilla Firefox<138.0
Mozilla Firefox>=128.0<128.10
Mozilla Thunderbird<128.10.0
Mozilla Thunderbird<138.0
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird<1:128.12.0+build1-0ubuntu0.22.04.1
1:128.12.0+build1-0ubuntu0.22.04.1
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<138
138
Mozilla Firefox ESR<128.10
128.10
Mozilla Thunderbird<128.10
128.10
debian/firefox
160.0-1
debian/firefox-esr
140.12.0esr-1~deb12u1153.7.0esr-1~deb12u1140.15.0esr-1~deb13u1153.6.0esr-1~deb13u1153.5.1esr-1153.7.0esr-1
debian/thunderbird
1:140.12.0esr-1~deb12u11:153.6.0esr-1~deb12u21:140.12.0esr-1~deb13u11:153.6.0esr-1~deb13u11:153.5.0esr-11:153.7.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 138
  2. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.23
  3. Upgrade

    Upgrade ubuntu/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:128.12.0+build1-0ubuntu0.22.04.1
  4. Upgrade

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

    Fixed in 138
  5. Upgrade

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

    Fixed in 128.10
  6. Upgrade

    Upgrade debian/firefox to a version that resolves this vulnerability.

    Fixed in 160.0-1
  7. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.12.0esr-1~deb12u1Fixed in 153.7.0esr-1~deb12u1Fixed in 140.15.0esr-1~deb13u1Fixed in 153.6.0esr-1~deb13u1Fixed in 153.5.1esr-1Fixed in 153.7.0esr-1
  8. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:153.6.0esr-1~deb12u2Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:153.6.0esr-1~deb13u1Fixed in 1:153.5.0esr-1Fixed in 1:153.7.0esr-1
  9. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 138
  10. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 128.10
  11. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 128.10

Event History

Apr 29, 2025
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
CVE Published
via MITRE·01:13 PM
Data Sourced
via MITRE·01:13 PM
Description
Data Sourced
via Red Hat·02:01 PM
DescriptionSeverityAffected Software
Data Sourced
via OSV·02:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:15 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-2025-4083?

CVE-2025-4083 has been classified as a high severity vulnerability due to its potential to allow sandbox escape.

2

How do I fix CVE-2025-4083?

To mitigate CVE-2025-4083, users should update Firefox and Thunderbird to versions 138 or later and Firefox ESR to versions 128.10 or later.

3

What impact does CVE-2025-4083 have on users?

CVE-2025-4083 could enable malicious content to execute in the top-level document's process, compromising user security.

4

Which versions of Firefox are affected by CVE-2025-4083?

CVE-2025-4083 affects Firefox versions earlier than 138 and Firefox ESR versions earlier than 128.

5

Does CVE-2025-4083 affect Thunderbird?

Yes, CVE-2025-4083 affects Thunderbird versions prior to 138 and Thunderbird ESR versions prior to 128.10.

Company

Resources

Contact

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