During TLS 1.2 exchanges, handshake hashes are generated which point to a message buffer. This saved data is used for later messages but in some cases, the handshake transcript can exceed the space available in the current buffer, causing the allocation of a new buffer. This leaves a pointer pointing to the old, freed buffer, resulting in a use-after-free when handshake hashes are then calculated afterwards. This can result in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.
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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Firefox | Mozilla | 52.4.0 (including) | 52.4.0 (including) |
| Firefox | Mozilla | 56.0 (including) | 56.0 (including) |
| Thunderbird | Mozilla | 52.4.0 (including) | 52.4.0 (including) |
| Red Hat Enterprise Linux 6 | RedHat | nss-0:3.28.4-4.el6_9 | * |
| Red Hat Enterprise Linux 7 | RedHat | nss-0:3.28.4-12.el7_4 | * |
| Firefox | Ubuntu | artful | * |
| Firefox | Ubuntu | bionic | * |
| Firefox | Ubuntu | cosmic | * |
| Firefox | Ubuntu | devel | * |
| Firefox | Ubuntu | trusty | * |
| Firefox | Ubuntu | upstream | * |
| Firefox | Ubuntu | xenial | * |
| Firefox | Ubuntu | zesty | * |
| Nss | Ubuntu | artful | * |
| Nss | Ubuntu | bionic | * |
| Nss | Ubuntu | cosmic | * |
| Nss | Ubuntu | devel | * |
| Nss | Ubuntu | esm-infra-legacy/trusty | * |
| Nss | Ubuntu | esm-infra/bionic | * |
| Nss | Ubuntu | esm-infra/xenial | * |
| Nss | Ubuntu | trusty | * |
| Nss | Ubuntu | trusty/esm | * |
| Nss | Ubuntu | xenial | * |
| Nss | Ubuntu | zesty | * |
| Thunderbird | Ubuntu | artful | * |
| Thunderbird | Ubuntu | bionic | * |
| Thunderbird | Ubuntu | cosmic | * |
| Thunderbird | Ubuntu | devel | * |
| Thunderbird | Ubuntu | trusty | * |
| Thunderbird | Ubuntu | upstream | * |
| Thunderbird | Ubuntu | xenial | * |
| Thunderbird | Ubuntu | zesty | * |