Mozilla Firefox (en-US) 121.0
Mozilla Firefox (en-US) 121.0, released December 20, 2023, fixes 15 CVEs in Mozilla Firefox (en-US). None of them is reported as exploited. Patch Radar priority: High. The latest Mozilla Firefox (en-US) is 159.0, which also fixes every one of these CVEs.
Superseded. The latest Mozilla Firefox (en-US) is 159.0, which also fixes every CVE on this page. Install that instead.
Priority of the 15 CVEs
Applies to
| Product | Version |
|---|---|
| Mozilla Firefox (en-US) | 121.0 |
CVEs this fix closes
| Priority | CVE | Title | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|
| High | CVE-2023-6856 | Mozilla Firefox ESR and 5 others: The WebGL `DrawElementsInstanced` method was susceptible to a heap buffer overflow when used on systems… | 8.8 | 0.2063 | None reported |
| High | CVE-2023-6858 | Mozilla Firefox ESR and 5 others: Out-of-bounds Write | 8.8 | 0.0154 | None reported |
| High | CVE-2023-6861 | Mozilla Firefox ESR and 5 others: The `nsWindow::PickerOpen(void)` method was susceptible to a heap buffer overflow when running in headless… | 8.8 | 0.0141 | None reported |
| High | CVE-2023-6864 | Mozilla Firefox ESR and 5 others: Memory safety bugs present in Firefox 120, Firefox ESR 115.5, and Thunderbird 115.5. | 8.8 | 0.0119 | None reported |
| High | CVE-2023-6859 | Mozilla Firefox ESR and 5 others: A use-after-free condition affected TLS socket creation when under memory pressure. | 8.8 | 0.0109 | None reported |
| High | CVE-2023-6863 | Mozilla Firefox ESR and 5 others: The `ShutdownObserver()` was susceptible to potentially undefined behavior due to its reliance on a dynamic… | 8.8 | 0.0104 | None reported |
| High | CVE-2023-6865 | Mozilla Firefox ESR and 3 others: `EncryptingOutputStream` was susceptible to exposing uninitialized data. | 7.5 | 0.0089 | None reported |
| High | CVE-2023-6873 | Mozilla Firefox ESR and 3 others: Memory safety bugs present in Firefox 120. | 8.8 | 0.0085 | None reported |
| High | CVE-2023-6866 | Mozilla Firefox ESR and 3 others: TypedArrays can be fallible and lacked proper exception handling. | 8.8 | 0.0068 | None reported |
| Routine | CVE-2023-6860 | Mozilla Firefox ESR and 5 others: The `VideoBridge` allowed any content process to use textures produced by remote decoders. | 6.5 | 0.0096 | None reported |
| Routine | CVE-2023-6135 | Mozilla Firefox ESR and 3 others: Multiple NSS NIST curves were susceptible to a side-channel attack known as "Minerva". | 4.3 | 0.0071 | None reported |
| Routine | CVE-2023-6867 | Mozilla Firefox ESR and 3 others: The timing of a button click causing a popup to disappear was approximately the same length as the anti-clickjacking… | 6.1 | 0.0068 | None reported |
| Routine | CVE-2023-6872 | Mozilla Firefox ESR and 3 others: Browser tab titles were being leaked by GNOME to system logs. | 6.5 | 0.0065 | None reported |
| Routine | CVE-2023-6869 | Mozilla Firefox ESR and 3 others: A `<dialog>` element could have been manipulated to paint content outside of a sandboxed iframe. | 6.5 | 0.0056 | None reported |
| Routine | CVE-2023-6871 | Mozilla Firefox ESR and 3 others: Under certain conditions, Firefox did not display a warning when a user attempted to navigate to a new… | 4.3 | 0.0049 | None reported |
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