CVE-2021-4128
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected;...
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected; resulting in memory corruption and a potentially exploitable crash.<br>This bug only affects Firefox on MacOS. Other operating systems are unaffected.. This vulnerability affects Firefox < 95.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected; resulting in memory corruption and a potentially exploitable crash.<br>This bug only affects Firefox on MacOS. Other operating systems are unaffected.. This vulnerability affects Firefox < 95.
- Record
CVE-2021-4128- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
CVE List
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected; resulting in memory corruption and a potentially exploitable crash.<br>This bug only affects Firefox on MacOS. Other operating systems are unaffected.. This vulnerability affects Firefox < 95.
- Record
CVE-2021-4128- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
EUVDEUVD-2021-34002
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected; resulting in memory corruption and a potentially exploitable crash.<br>This bug only affects Firefox on MacOS. Other operating systems are unaffected.. This vulnerability affects Firefox < 95.
- Record
EUVD-2021-34002- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-qx74-qh3q-h8rj
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected;...
When transitioning in and out of fullscreen mode, a graphics object was not correctly protected; resulting in memory corruption and a potentially exploitable crash.<br>This bug only affects Firefox on MacOS. Other operating systems are unaffected.. This vulnerability affects Firefox < 95.
- Record
GHSA-qx74-qh3q-h8rj- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-4128 is a medium vulnerability (CVSS 6.5) in Mozilla Firefox, published December 22, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.57%, the 47th percentile. No source names a fixed version.