CVE-2020-12395

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

Mozilla developers and community members reported memory safety bugs present in Firefox 75 and Firefox ESR 68.7. 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 ESR < 68.8, Firefox < 76, and Thunderbird < 68.8.0.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
82%
KEV
Not listed

Published

May 26, 2020

Last Modified

November 21, 2024

Advisory Details (6)

Auto-updated Aug 16, 2026
No patch confirmed yet.
generic

Mozilla Firefox: Multiple vulnerabilities (GLSA 202005-04) — Gentoo security

https://security.gentoo.org/glsa/202005-04
generic

Mozilla Thunderbird: Multiple vulnerabilities (GLSA 202005-03) — Gentoo security

https://security.gentoo.org/glsa/202005-03
generic

Client Challenge

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1595886%2C1611482%2C1614704%2C1624098%2C1625749%2C1626382%2C1628076%2C1631508
generic

Security Vulnerabilities fixed in Thunderbird 68.8.0 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2020-18/
generic

Security Vulnerabilities fixed in Firefox ESR 68.8 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2020-17/
generic

Security Vulnerabilities fixed in Firefox 76 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2020-16/

Patch Availability(12)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuxul-ext-lightning (1:68.8.0+build2-0ubuntu0.18.04.2) @ bionic2026-05-27ubuntu
ubuntufirefox-mozsymbols (76.0+build2-0ubuntu0.16.04.1) @ xenial2026-05-27ubuntu
redhatthunderbird-0:68.8.0-1.el6_102020-05-11redhat
redhatthunderbird-0:68.8.0-1.el7_82020-05-11redhat
redhatthunderbird-0:68.8.0-1.el8_02020-05-11redhat
redhatthunderbird-0:68.8.0-1.el8_22020-05-11redhat
redhatthunderbird-0:68.8.0-1.el8_12020-05-11redhat
redhatfirefox-0:68.8.0-1.el6_102020-05-06redhat
redhatfirefox-0:68.8.0-1.el8_02020-05-06redhat
redhatfirefox-0:68.8.0-1.el7_82020-05-06redhat
redhatfirefox-0:68.8.0-1.el8_22020-05-06redhat
redhatfirefox-0:68.8.0-1.el8_12020-05-06redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(14 across 7 ecosystems)
Debian:10(2)
PackageVulnerable rangeFixed inDependents
firefox-esr60.7.2esr-1 ... 68.8.0esr-1~deb9u1 (46 versions)68.8.0esr-1~deb10u1—
thunderbird1:60.7.2-1 ... 1:68.8.0-1~deb9u1 (46 versions)1:68.8.0-1~deb10u1—
Debian:11(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—68.8.0esr-1—
thunderbird—1:68.8.0-1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—68.8.0esr-1—
thunderbird—1:68.8.0-1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—68.8.0esr-1—
thunderbird—1:68.8.0-1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr—68.8.0esr-1—
thunderbird—1:68.8.0-1—
Debian:8(2)
PackageVulnerable rangeFixed inDependents
firefox-esr45.0.1esr-1 ... 68.7.0esr-1~deb9u1 (190 versions)68.8.0esr-1~deb8u1—
thunderbird1.5-4 ... 1:68.7.0-1~deb9u1 (126 versions)1:68.8.0-1~deb8u1—
Debian:9(2)
PackageVulnerable rangeFixed inDependents
firefox-esr45.9.0esr-1 ... 68.8.0esr-1~deb8u1 (153 versions)68.8.0esr-1~deb9u1—
thunderbird1.5-4 ... 1:68.8.0-1~deb8u1 (127 versions)1:68.8.0-1~deb9u1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(12)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 126 total refreshes for this CVE.

  1. 2026-08-20 22:51 UTCEPSS rescore
  2. 2026-08-20 21:01 UTCOSV refresh
  3. 2026-08-19 17:00 UTCEPSS rescore
  4. 2026-08-18 13:44 UTCEPSS rescore
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  16. 2026-08-05 13:11 UTCOSV refresh
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  25. 2026-07-26 14:51 UTCEPSS rescore
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  1. 2026-07-25 14:14 UTCEPSS rescore
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  5. 2026-07-23 01:48 UTCEG score recompute
  6. 2026-07-22 22:33 UTCEG score recompute
  7. 2026-07-22 14:05 UTCEPSS rescore
  8. 2026-07-21 15:22 UTCEPSS rescore
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  10. 2026-07-20 17:04 UTCEPSS rescore
  11. 2026-07-19 14:28 UTCEPSS rescore
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  13. 2026-07-19 12:00 UTCOSV refresh
  14. 2026-07-19 02:26 UTCEPSS rescore
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  23. 2026-07-12 05:44 UTCEPSS rescore
  24. 2026-07-11 08:24 UTCEPSS rescore
  25. 2026-07-09 19:06 UTCEPSS rescore
  26. 2026-07-08 15:11 UTCEPSS rescore
  27. 2026-07-07 13:43 UTCEPSS rescore
  28. 2026-07-06 16:25 UTCEPSS rescore
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  30. 2026-07-06 02:20 UTCEPSS rescore
  31. 2026-07-05 02:27 UTCEPSS rescore
  32. 2026-07-04 06:28 UTCEPSS rescore
  33. 2026-07-01 20:31 UTCOSV refresh
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  36. 2026-06-30 23:20 UTCEPSS rescore
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  41. 2026-06-27 03:06 UTCEPSS rescore
  42. 2026-06-25 13:47 UTCEPSS rescore
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  46. 2026-06-23 21:31 UTCEPSS rescore
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  48. 2026-06-21 14:54 UTCEPSS rescore
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  54. 2026-06-18 17:50 UTCEPSS rescore
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  62. 2026-06-14 23:15 UTCEPSS rescore
  63. 2026-06-14 02:13 UTCOSV refresh
  64. 2026-06-13 22:58 UTCEPSS rescore
  65. 2026-06-13 22:58 UTCEPSS rescore
  66. 2026-06-12 23:09 UTCEPSS rescore
  67. 2026-06-11 13:58 UTCEPSS rescore
  68. 2026-06-10 22:16 UTCEPSS rescore
  69. 2026-06-10 22:16 UTCEPSS rescore
  70. 2026-06-10 13:20 UTCEPSS rescore
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  73. 2026-06-07 15:23 UTCEPSS rescore
  74. 2026-06-07 15:23 UTCEPSS rescore
  75. 2026-06-06 13:45 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2020-12395?
CVE-2020-12395 is a critical vulnerability published on May 26, 2020. Mozilla developers and community members reported memory safety bugs present in Firefox 75 and Firefox ESR 68.7. 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…
When was CVE-2020-12395 disclosed?
CVE-2020-12395 was first published in the National Vulnerability Database on May 26, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-12395 actively exploited?
CVE-2020-12395 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 18.4% of all scored CVEs.
What is the CVSS score of CVE-2020-12395?
CVE-2020-12395 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-12395?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-12395, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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