CVE-2025-8033: Incorrect JavaScript state machine for generators

Published Jul 22, 2025
·
Updated

The JavaScript engine did not handle closed generators correctly and it was possible to resume them leading to a nullptr deref. This vulnerability was fixed in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

Other sources

The JavaScript engine did not handle closed generators correctly and it was possible to resume them leading to a nullptr deref. This vulnerability affects Firefox < 141, Firefox ESR < 115.26, Firefox ESR < 128.13, Firefox ESR < 140.1, Thunderbird < 141, Thunderbird < 128.13, and Thunderbird < 140.1.

— Red Hat

Affected Software

27 affected componentsFixes available
Mozilla Firefox ESR<115.26
115.26
Mozilla Firefox ESR<140.1
140.1
Mozilla Thunderbird<140.1
140.1
Mozilla Thunderbird<141
141
Mozilla Firefox<115.26.0
Mozilla Firefox<141.0
Mozilla Firefox>=128.0<128.13.0
Mozilla Firefox>=140.0<140.1.0
Mozilla Thunderbird<128.13.0
Mozilla Thunderbird<141.0
Mozilla Thunderbird>=140.0<140.1.0
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird<1:140.7.1+build1-0ubuntu0.22.04.1
1:140.7.1+build1-0ubuntu0.22.04.1
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<141
141
Mozilla Firefox ESR<128.13
128.13
Mozilla Thunderbird<128.13
128.13
debian/firefox
160.0-1
debian/firefox-esr
140.12.0esr-1~deb12u1153.7.0esr-1~deb12u1140.15.0esr-1~deb13u1153.7.0esr-1~deb13u1153.5.1esr-1153.7.0esr-1
debian/thunderbird
1:140.12.0esr-1~deb12u11:153.7.0esr-1~deb12u11:140.12.0esr-1~deb13u11:153.7.0esr-1~deb13u11:153.5.0esr-11:153.7.0esr-1

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 115.26
  2. Upgrade

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

    Fixed in 140.1
  3. Upgrade

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

    Fixed in 141
  4. Upgrade

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

    Fixed in 1:140.7.1+build1-0ubuntu0.22.04.1
  5. Upgrade

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

    Fixed in 128.13
  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 153.7.0esr-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 1:153.7.0esr-1~deb12u1Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:153.7.0esr-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 141
  10. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.26
  11. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 128.13
  12. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.1
  13. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 141
  14. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 128.13
  15. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 140.1

Event History

Jul 22, 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·08:49 PM
Data Sourced
via MITRE·08:49 PM
Description
Data Sourced
via Red Hat·09:02 PM
DescriptionSeverityAffected Software
Data Sourced
via OSV·09:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·09:15 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-2025-8033?

CVE-2025-8033 is classified as a moderate severity vulnerability due to the potential for a null pointer dereference leading to application crashes.

2

How do I fix CVE-2025-8033?

To fix CVE-2025-8033, update affected versions of Mozilla Firefox and Firefox ESR to the latest patched versions.

3

Which versions of Firefox are affected by CVE-2025-8033?

CVE-2025-8033 affects Firefox versions up to 141 and Firefox ESR versions up to 115.26.

4

What type of vulnerability is CVE-2025-8033?

CVE-2025-8033 is a JavaScript engine vulnerability related to improper handling of closed generators.

5

Can CVE-2025-8033 be exploited remotely?

CVE-2025-8033 has the potential for remote exploitation as it can lead to application crashes.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203