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CVE-2020-12420
When trying to connect to a STUN server, a race condition could have caused a use-after-free of a pointer, leading to memory corruption…
High8.8EPSS 1.9%
- Published
- Updated
- Reserved
- Assigned by
- mozilla
Description
When trying to connect to a STUN server, a race condition could have caused a use-after-free of a pointer, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.10, Firefox < 78, and Thunderbird < 68.10.0.
Timeline
ID reserved
By mozilla
- 2 months later
· 2 months later
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
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)
- 1.9% · top 21% of all CVEs (7 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
- Use-After-Free when trying to connect to a STUN server
- CWE-362 (opens in a new tab)All about CWE-362 and its CVEs
- CWE-416 (opens in a new tab)All about CWE-416 and its CVEs
Affected products
- affected unspecified – < 68.10
- affected unspecified – < 78
- affected unspecified – < 68.10.0
References (11)
- https://www.mozilla.org/security/advisories/mfsa2020-24/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2020-26/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2020-25/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1643437 (opens in a new tab)x_refsource_MISCx_transferred
- openSUSE-SU-2020:0967 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2020:0982 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2020:0983 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2020:1017 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- USN-4421-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- GLSA-202007-09 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- GLSA-202007-10 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_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-2020-12420)Record last updated .