When creating a callback over IPC for showing the Color Picker window, multiple of the same callbacks could have been created at a time and eventually all simultaneously destroyed as soon as one of the callbacks finished. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox < 117, Firefox ESR < 102.15, Firefox ESR < 115.2, Thunderbird < 102.15, and Thunderbird < 115.2.
https://www.mozilla.org/security/advisories/mfsa2023-38/
https://www.mozilla.org/security/advisories/mfsa2023-37/
https://www.mozilla.org/security/advisories/mfsa2023-36/
https://www.mozilla.org/security/advisories/mfsa2023-35/