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CVE-2020-12399NSS has shown timing differences when performing DSA signatures, which was exploitable and could eventually leak private keys. This…
- 4.4MediumCVSS base score
- 0.65%Exploitation in 30 daysEPSS · top 48% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
NSS has shown timing differences when performing DSA signatures, which was exploitable and could eventually leak private keys. This vulnerability affects Thunderbird < 68.9.0, Firefox < 77, and Firefox ESR < 68.9.
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 | Medium4.4 | CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.65% · top 48% of all CVEs (13 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.4.
Affected products
- affected unspecified – < 68.9.0
- affected unspecified – < 77
- affected unspecified – < 68.9
References
References8
- https://www.mozilla.org/security/advisories/mfsa2020-20/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2020-21/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2020-22/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1631576 (opens in a new tab)x_refsource_MISCx_transferred
- DSA-4726 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- USN-4421-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- GLSA-202007-49 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- [debian-lts-announce] 20200929 [SECURITY] [DLA 2388-1] nss security update (opens in a new tab)mailing-listx_refsource_MLISTx_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)
- EUVD EUVD-2020-4711 (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://cveledger.app/cve/CVE-2020-12399)Record last updated .