When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified. This results in a use-after-free and we presume that with enough effort it could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 68.12 and Thunderbird < 68.12.
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| https://www.mozilla.org/security/advisories/mfsa2020-40/ | release notes vendor advisory |
| https://www.mozilla.org/security/advisories/mfsa2020-37/ | release notes vendor advisory |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1656957 | vendor advisory issue tracking permissions required |