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CVE-2021-23964
Mozilla developers reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6. Some of these bugs showed evidence of memory…
High8.8EPSS 1.4%
- Published
- Updated
- Reserved
- Assigned by
- mozilla
Description
Mozilla developers reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 1.4% · top 28% of all CVEs (6 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
- Memory safety bugs fixed in Firefox 85 and Firefox ESR 78.7
- CWE-787 (opens in a new tab)All about CWE-787 and its CVEs
Affected products
- affected < 85
- affected < 78.7
- affected < 78.7
References (4)
- https://www.mozilla.org/security/advisories/mfsa2021-03/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2021-04/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2021-05/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1662507%2C1666285%2C1673526%2C1674278%2C1674835%2C1675097%2C1675844%2C1675868%2C1677590%2C1677888%2C1680410%2C1681268%2C1682068%2C1682938%2C1683736%2C1685260%2C1685925 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-23964)Record last updated .