It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Firefox | Mozilla | * | 115.21.0 (excluding) |
| Firefox | Mozilla | * | 136.0 (excluding) |
| Firefox | Mozilla | 116.0 (including) | 128.8.0 (excluding) |
| Thunderbird | Mozilla | * | 128.8.0 (excluding) |
| Thunderbird | Mozilla | 129.0 (including) | 136.0 (excluding) |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | RedHat | firefox-0:128.8.0-1.el7_9 | * |
| Red Hat Enterprise Linux 8 | RedHat | firefox-0:128.8.0-1.el8_10 | * |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | RedHat | firefox-0:128.8.0-1.el8_2 | * |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | RedHat | firefox-0:128.8.0-1.el8_4 | * |
| Red Hat Enterprise Linux 8.4 Telecommunications Update Service | RedHat | firefox-0:128.8.0-1.el8_4 | * |
| Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions | RedHat | firefox-0:128.8.0-1.el8_4 | * |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | RedHat | firefox-0:128.8.0-1.el8_6 | * |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | RedHat | firefox-0:128.8.0-1.el8_6 | * |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | RedHat | firefox-0:128.8.0-1.el8_6 | * |
| Red Hat Enterprise Linux 8.8 Extended Update Support | RedHat | firefox-0:128.8.0-1.el8_8 | * |
| Red Hat Enterprise Linux 9 | RedHat | firefox-0:128.8.0-1.el9_5 | * |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | RedHat | firefox-0:128.8.0-1.el9_0 | * |
| Red Hat Enterprise Linux 9.2 Extended Update Support | RedHat | firefox-0:128.8.0-1.el9_2 | * |
| Red Hat Enterprise Linux 9.4 Extended Update Support | RedHat | firefox-0:128.8.0-1.el9_4 | * |
| Firefox | Ubuntu | focal | * |
| Mozjs102 | Ubuntu | esm-apps/noble | * |
| Mozjs102 | Ubuntu | jammy | * |
| Mozjs102 | Ubuntu | noble | * |
| Mozjs115 | Ubuntu | noble | * |
| Mozjs115 | Ubuntu | oracular | * |
| Mozjs115 | Ubuntu | plucky | * |
| Mozjs52 | Ubuntu | esm-infra/bionic | * |
| Mozjs52 | Ubuntu | focal | * |
| Mozjs68 | Ubuntu | esm-infra/focal | * |
| Mozjs68 | Ubuntu | focal | * |
| Mozjs78 | Ubuntu | jammy | * |
| Mozjs91 | Ubuntu | jammy | * |
| Thunderbird | Ubuntu | focal | * |
| Thunderbird | Ubuntu | jammy | * |
| Thunderbird | Ubuntu | upstream | * |
Potential Mitigations
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1944126
- https://www.mozilla.org/security/advisories/mfsa2025-14/
- https://www.mozilla.org/security/advisories/mfsa2025-15/
- https://www.mozilla.org/security/advisories/mfsa2025-16/
- https://www.mozilla.org/security/advisories/mfsa2025-17/
- https://www.mozilla.org/security/advisories/mfsa2025-18/
- https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html