CVE-2019-9800

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 32% of all CVEs by exploit prediction. 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
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 9.8Exploit: NoneExposed: 0

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
9.8(medium)
EPSS
75.5%
KEV
Not listed

Published

July 23, 2019

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Jul 6, 2026
No patch confirmed yet.
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 / EcosystemFixed in / 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.

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 10× in last 7d / 50× 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.

  1. 2026-07-06 16:25 UTCEPSS rescore
  2. 2026-07-06 16:25 UTCEPSS rescore
  3. 2026-07-06 02:20 UTCEPSS rescore
  4. 2026-07-05 02:27 UTCEPSS rescore
  5. 2026-07-04 06:28 UTCEPSS rescore
  6. 2026-07-03 07:26 UTCOSV refresh
  7. 2026-07-01 15:03 UTCEPSS rescore
  8. 2026-07-01 15:03 UTCEPSS rescore
  9. 2026-06-30 23:20 UTCEPSS rescore
  10. 2026-06-30 23:20 UTCEPSS rescore
  11. 2026-06-29 14:04 UTCEPSS rescore
  12. 2026-06-29 14:04 UTCEPSS rescore
  13. 2026-06-28 14:05 UTCEPSS rescore
  14. 2026-06-28 04:54 UTCEPSS rescore
  15. 2026-06-28 04:54 UTCEPSS rescore
  16. 2026-06-27 03:06 UTCEPSS rescore
  17. 2026-06-25 13:47 UTCEPSS rescore
  18. 2026-06-25 13:47 UTCEPSS rescore
  19. 2026-06-24 14:03 UTCEPSS rescore
  20. 2026-06-24 14:03 UTCEPSS rescore
  21. 2026-06-23 21:31 UTCEPSS rescore
  22. 2026-06-23 21:31 UTCEPSS rescore
  23. 2026-06-22 14:23 UTCEPSS rescore
  24. 2026-06-22 14:23 UTCEPSS rescore
  25. 2026-06-21 14:54 UTCEPSS rescore
Show 52 more
  1. 2026-06-21 14:54 UTCEPSS rescore
  2. 2026-06-21 01:57 UTCEPSS rescore
  3. 2026-06-21 01:57 UTCEPSS rescore
  4. 2026-06-19 19:23 UTCEPSS rescore
  5. 2026-06-19 19:23 UTCEPSS rescore
  6. 2026-06-18 17:50 UTCEPSS rescore
  7. 2026-06-18 17:50 UTCEPSS rescore
  8. 2026-06-17 17:50 UTCEPSS rescore
  9. 2026-06-16 17:50 UTCEPSS rescore
  10. 2026-06-15 17:46 UTCEPSS rescore
  11. 2026-06-14 23:15 UTCEPSS rescore
  12. 2026-06-14 23:15 UTCEPSS rescore
  13. 2026-06-14 22:13 UTCOSV refresh
  14. 2026-06-13 22:58 UTCEPSS rescore
  15. 2026-06-12 23:09 UTCEPSS rescore
  16. 2026-06-12 23:09 UTCEPSS rescore
  17. 2026-06-11 13:58 UTCEPSS rescore
  18. 2026-06-10 22:16 UTCEPSS rescore
  19. 2026-06-10 22:16 UTCEPSS rescore
  20. 2026-06-10 13:19 UTCEPSS rescore
  21. 2026-06-08 14:15 UTCEPSS rescore
  22. 2026-06-08 14:15 UTCEPSS rescore
  23. 2026-06-08 14:15 UTCEPSS rescore
  24. 2026-06-07 15:23 UTCEPSS rescore
  25. 2026-06-07 15:23 UTCEPSS rescore
  26. 2026-06-06 13:45 UTCEPSS rescore
  27. 2026-06-06 13:45 UTCEPSS rescore
  28. 2026-06-05 22:45 UTCEPSS rescore
  29. 2026-06-05 06:08 UTCEPSS rescore
  30. 2026-06-04 13:10 UTCEPSS rescore
  31. 2026-06-04 13:10 UTCEPSS rescore
  32. 2026-06-02 20:11 UTCEPSS rescore
  33. 2026-06-02 20:11 UTCEPSS rescore
  34. 2026-06-01 13:50 UTCEPSS rescore
  35. 2026-06-01 13:50 UTCEPSS rescore
  36. 2026-05-31 22:29 UTCEPSS rescore
  37. 2026-05-31 22:29 UTCEPSS rescore
  38. 2026-05-31 00:14 UTCEPSS rescore
  39. 2026-05-31 00:14 UTCEPSS rescore
  40. 2026-05-29 13:42 UTCEPSS rescore
  41. 2026-05-28 13:43 UTCEPSS rescore
  42. 2026-05-28 13:43 UTCEPSS rescore
  43. 2026-05-27 17:03 UTCEG score recompute
  44. 2026-05-27 17:03 UTCVendor advisory
  45. 2026-05-27 17:03 UTCGHSA enrichment
  46. 2026-05-27 13:39 UTCEPSS rescore
  47. 2026-05-27 13:38 UTCEPSS rescore
  48. 2026-05-26 13:42 UTCEPSS rescore
  49. 2026-05-26 07:17 UTCEPSS rescore
  50. 2026-05-26 07:17 UTCEPSS rescore
  51. 2026-05-26 07:17 UTCEPSS rescore
  52. 2026-05-24 16:47 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 in the National Vulnerability Database 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 75.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-9800, 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.

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