CVE-2019-9800

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 1.7% (76th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, 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: 1.7%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Mozilla developers and community members reported memory safety bugs present in Firefox 66, Firefox ESR 60.6, and Thunderbird 60.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
49
EG Risk 49/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
1.7%
EPSS %ILE
76th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 23, 2019

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Oct 4, 2026
Patch available.
generic

Security vulnerabilities fixed in Thunderbird 60.7 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-15/
generic

Security vulnerabilities fixed in Firefox ESR 60.7 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-14/
generic

Security vulnerabilities fixed in Firefox 67 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2019-13/
generic

Client Challenge

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1540166%2C1534593%2C1546327%2C1540136%2C1538736%2C1538042%2C1535612%2C1499719%2C1499108%2C1538619%2C1535194%2C1516325%2C1542324%2C1542097%2C1532465%2C1533554%2C1541580

Patch Availability(8)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntuxul-ext-lightning (1:60.7.0+build1-0ubuntu0.18.04.1) @ bionic2026-05-27ubuntu
ubuntufirefox-testsuite (67.0+build2-0ubuntu0.16.04.1) @ xenial2026-05-27ubuntu
redhatthunderbird-0:60.7.0-1.el6_102019-06-03redhat
redhatthunderbird-0:60.7.0-1.el8_02019-06-03redhat
redhatthunderbird-0:60.7.0-1.el7_62019-06-03redhat
redhatfirefox-0:60.7.0-1.el8_02019-05-23redhat
redhatfirefox-0:60.7.0-1.el6_102019-05-23redhat
redhatfirefox-0:60.7.0-1.el7_62019-05-23redhat

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

(12 across 6 ecosystems)
Debian:11(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 60.7.0esr-1: fixed in 60.7.0esr-1
—
thunderbird—
  • every version up to 1:60.7.0-1: fixed in 1:60.7.0-1
—
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 60.7.0esr-1: fixed in 60.7.0esr-1
—
thunderbird—
  • every version up to 1:60.7.0-1: fixed in 1:60.7.0-1
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 60.7.0esr-1: fixed in 60.7.0esr-1
—
thunderbird—
  • every version up to 1:60.7.0-1: fixed in 1:60.7.0-1
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 60.7.0esr-1: fixed in 60.7.0esr-1
—
thunderbird—
  • every version up to 1:60.7.0-1: fixed in 1:60.7.0-1
—
Debian:8(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr45.0.1esr-1 ... 60.6.3esr-1~deb9u1 (139 versions)
  • every version up to 60.7.0esr-1~deb8u1: fixed in 60.7.0esr-1~deb8u1
—
thunderbird1.5-4 ... 1:60.6.1-1~deb9u1 (74 versions)
  • every version up to 1:60.7.0-1~deb8u1: fixed in 1:60.7.0-1~deb8u1
—
Debian:9(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr45.9.0esr-1 ... 60.7.0esr-1~deb8u1 (102 versions)
  • every version up to 60.7.0esr-1~deb9u1: fixed in 60.7.0esr-1~deb9u1
—
thunderbird1.5-4 ... 1:60.7.0-1~deb8u1 (75 versions)
  • every version up to 1:60.7.0-1~deb9u1: fixed in 1:60.7.0-1~deb9u1
—

Weakness Classification(2)

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

All Vendor Advisories

(8)

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 5× in last 7d / 25× 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 165 total refreshes for this CVE.

  1. 2026-10-05 17:39 UTCEPSS rescore
  2. 2026-10-04 23:18 UTCEPSS rescore
  3. 2026-10-03 14:22 UTCEPSS rescore
  4. 2026-09-30 14:59 UTCEPSS rescore
  5. 2026-09-30 10:30 UTCEG score recompute
  6. 2026-09-28 00:13 UTCOSV refresh
  7. 2026-09-27 13:40 UTCEPSS rescore
  8. 2026-09-26 15:54 UTCEPSS rescore
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  20. 2026-09-12 14:56 UTCEPSS rescore
  21. 2026-09-11 14:48 UTCEPSS rescore
  22. 2026-09-11 09:32 UTCEPSS rescore
  23. 2026-09-08 08:19 UTCOSV refresh
  24. 2026-09-07 15:57 UTCEPSS rescore
  25. 2026-09-06 13:44 UTCEPSS rescore
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  1. 2026-09-05 15:24 UTCEPSS rescore
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  10. 2026-08-26 14:42 UTCEPSS rescore
  11. 2026-08-25 13:45 UTCEPSS rescore
  12. 2026-08-21 18:44 UTCOSV refresh
  13. 2026-08-20 22:51 UTCEPSS rescore
  14. 2026-08-19 17:00 UTCEPSS rescore
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  20. 2026-08-13 21:57 UTCEPSS rescore
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  23. 2026-08-08 16:33 UTCEPSS rescore
  24. 2026-08-07 16:23 UTCEPSS rescore
  25. 2026-08-06 13:43 UTCEPSS rescore
  26. 2026-08-06 02:51 UTCOSV refresh
  27. 2026-08-05 19:14 UTCEPSS rescore
  28. 2026-08-04 15:06 UTCEPSS rescore
  29. 2026-08-04 10:34 UTCEPSS rescore
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  36. 2026-07-26 14:51 UTCEPSS rescore
  37. 2026-07-25 14:14 UTCEPSS rescore
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  39. 2026-07-23 14:15 UTCEPSS rescore
  40. 2026-07-23 14:15 UTCEPSS rescore
  41. 2026-07-23 01:47 UTCEG score recompute
  42. 2026-07-22 22:30 UTCEG score recompute
  43. 2026-07-22 14:05 UTCEPSS rescore
  44. 2026-07-21 15:22 UTCEPSS rescore
  45. 2026-07-21 15:22 UTCEPSS rescore
  46. 2026-07-20 17:04 UTCEPSS rescore
  47. 2026-07-20 12:32 UTCOSV refresh
  48. 2026-07-19 14:28 UTCEPSS rescore
  49. 2026-07-19 14:28 UTCEPSS rescore
  50. 2026-07-19 02:26 UTCEPSS rescore
  51. 2026-07-19 02:26 UTCEPSS rescore
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  53. 2026-07-16 16:59 UTCEPSS rescore
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  59. 2026-07-12 05:44 UTCEPSS rescore
  60. 2026-07-11 08:24 UTCEPSS rescore
  61. 2026-07-09 19:06 UTCEPSS rescore
  62. 2026-07-08 15:11 UTCEPSS rescore
  63. 2026-07-07 13:43 UTCEPSS rescore
  64. 2026-07-06 16:25 UTCEPSS rescore
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  67. 2026-07-05 02:27 UTCEPSS rescore
  68. 2026-07-04 06:28 UTCEPSS rescore
  69. 2026-07-03 07:26 UTCOSV refresh
  70. 2026-07-01 15:03 UTCEPSS rescore
  71. 2026-07-01 15:03 UTCEPSS rescore
  72. 2026-06-30 23:20 UTCEPSS rescore
  73. 2026-06-30 23:20 UTCEPSS rescore
  74. 2026-06-29 14:04 UTCEPSS rescore
  75. 2026-06-29 14:04 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2019-9800?
CVE-2019-9800 is a critical vulnerability published on July 23, 2019. Mozilla developers and community members reported memory safety bugs present in Firefox 66, Firefox ESR 60.6, and Thunderbird 60.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This…
When was CVE-2019-9800 disclosed?
CVE-2019-9800 was first published on July 23, 2019, 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-2019-9800 actively exploited?
CVE-2019-9800 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.7% probability of exploitation in the next 30 days (76th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2019-9800?
CVE-2019-9800 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2019-9800?
A fix for CVE-2019-9800 is available: update to the fixed version the vendor names in its advisory.

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