CVE-2019-17026

HIGHNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 5 sources updated this weekExploited in the wild
8.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 43%CVSS: 8.8Exploit: NoneExposed: 0

A fix is available — apply it.

Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.

CVSS v3
8.8
EG Score
9.0(high)
EPSS
98.6%
KEV
⚠ Exploited

Published

March 2, 2020

Last Modified

November 4, 2025

Advisory Details (5)

Auto-updated Jun 1, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic

Mozilla Firefox: Multiple vulnerabilities (GLSA 202003-02) — Gentoo security

https://security.gentoo.org/glsa/202003-02
generic🔴 Active Exploitation

1607443 - (CVE-2019-17026) In-the-wild 0-day reported by Qihoo 360

https://bugzilla.mozilla.org/show_bug.cgi?id=1607443
generic

Packet Storm

http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.html
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Thunderbird 68.4.1 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2020-04/
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Firefox 72.0.1 and Firefox ESR 68.4.1 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2020-03/

Patch Availability(11)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntufirefox-mozsymbols (72.0.1+build1-0ubuntu0.16.04.1) @ xenial2026-07-16ubuntu
ubuntuxul-ext-lightning (1:68.7.0+build1-0ubuntu0.16.04.2) @ xenial2026-07-16ubuntu
ubuntuxul-ext-lightning (1:68.4.1+build1-0ubuntu0.19.10.1) @ eoan2026-07-16ubuntu
redhatthunderbird-0:68.4.1-2.el8_02020-01-30redhat
redhatfirefox-0:68.4.1-1.el8_02020-01-30redhat
redhatthunderbird-0:68.4.1-2.el8_12020-01-16redhat
redhatthunderbird-0:68.4.1-2.el6_102020-01-16redhat
redhatthunderbird-0:68.4.1-2.el7_72020-01-16redhat
redhatfirefox-0:68.4.1-1.el8_12020-01-14redhat
redhatfirefox-0:68.4.1-1.el6_102020-01-13redhat
redhatfirefox-0:68.4.1-1.el7_72020-01-13redhat

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(1)

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

All Vendor Advisories

(11)

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 153× in last 7d / 625× 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 965 total refreshes for this CVE.

  1. 2026-07-16 03:08 UTCEG score recompute
  2. 2026-07-16 03:08 UTCVendor advisory
  3. 2026-07-16 03:08 UTCGHSA enrichment
  4. 2026-07-15 23:27 UTCEG score recompute
  5. 2026-07-15 23:27 UTCVendor advisory
  6. 2026-07-15 23:26 UTCGHSA enrichment
  7. 2026-07-15 19:45 UTCEG score recompute
  8. 2026-07-15 19:45 UTCVendor advisory
  9. 2026-07-15 19:45 UTCGHSA enrichment
  10. 2026-07-15 16:55 UTCEPSS rescore
  11. 2026-07-15 16:55 UTCEPSS rescore
  12. 2026-07-15 16:49 UTCCISA KEV update
  13. 2026-07-15 16:04 UTCEG score recompute
  14. 2026-07-15 16:04 UTCVendor advisory
  15. 2026-07-15 16:04 UTCGHSA enrichment
  16. 2026-07-15 15:04 UTCCISA KEV update
  17. 2026-07-15 12:22 UTCEG score recompute
  18. 2026-07-15 12:22 UTCVendor advisory
  19. 2026-07-15 12:21 UTCGHSA enrichment
  20. 2026-07-15 08:39 UTCEG score recompute
  21. 2026-07-15 08:39 UTCVendor advisory
  22. 2026-07-15 08:39 UTCGHSA enrichment
  23. 2026-07-15 04:57 UTCEG score recompute
  24. 2026-07-15 04:57 UTCVendor advisory
  25. 2026-07-15 04:57 UTCGHSA enrichment
Show 75 more
  1. 2026-07-15 01:16 UTCEG score recompute
  2. 2026-07-15 01:16 UTCVendor advisory
  3. 2026-07-15 01:16 UTCGHSA enrichment
  4. 2026-07-14 21:35 UTCEG score recompute
  5. 2026-07-14 21:35 UTCVendor advisory
  6. 2026-07-14 21:35 UTCGHSA enrichment
  7. 2026-07-14 18:05 UTCCISA KEV update
  8. 2026-07-14 17:54 UTCEG score recompute
  9. 2026-07-14 17:54 UTCVendor advisory
  10. 2026-07-14 17:54 UTCGHSA enrichment
  11. 2026-07-14 14:06 UTCEG score recompute
  12. 2026-07-14 14:06 UTCVendor advisory
  13. 2026-07-14 14:05 UTCGHSA enrichment
  14. 2026-07-14 10:24 UTCEG score recompute
  15. 2026-07-14 10:24 UTCVendor advisory
  16. 2026-07-14 10:24 UTCGHSA enrichment
  17. 2026-07-14 06:43 UTCEG score recompute
  18. 2026-07-14 06:43 UTCVendor advisory
  19. 2026-07-14 06:43 UTCGHSA enrichment
  20. 2026-07-14 02:59 UTCEG score recompute
  21. 2026-07-14 02:59 UTCVendor advisory
  22. 2026-07-14 02:59 UTCGHSA enrichment
  23. 2026-07-13 23:19 UTCEG score recompute
  24. 2026-07-13 23:19 UTCVendor advisory
  25. 2026-07-13 23:19 UTCGHSA enrichment
  26. 2026-07-13 22:27 UTCEPSS rescore
  27. 2026-07-13 19:38 UTCEG score recompute
  28. 2026-07-13 19:38 UTCVendor advisory
  29. 2026-07-13 19:38 UTCGHSA enrichment
  30. 2026-07-13 17:07 UTCCISA KEV update
  31. 2026-07-13 15:57 UTCEG score recompute
  32. 2026-07-13 15:57 UTCVendor advisory
  33. 2026-07-13 15:56 UTCGHSA enrichment
  34. 2026-07-13 12:14 UTCEG score recompute
  35. 2026-07-13 12:14 UTCVendor advisory
  36. 2026-07-13 12:14 UTCGHSA enrichment
  37. 2026-07-13 08:32 UTCEG score recompute
  38. 2026-07-13 08:32 UTCVendor advisory
  39. 2026-07-13 08:31 UTCGHSA enrichment
  40. 2026-07-13 06:10 UTCEPSS rescore
  41. 2026-07-13 06:10 UTCEPSS rescore
  42. 2026-07-13 04:48 UTCEG score recompute
  43. 2026-07-13 04:48 UTCVendor advisory
  44. 2026-07-13 04:48 UTCGHSA enrichment
  45. 2026-07-13 01:07 UTCEG score recompute
  46. 2026-07-13 01:07 UTCVendor advisory
  47. 2026-07-13 01:07 UTCGHSA enrichment
  48. 2026-07-12 21:26 UTCEG score recompute
  49. 2026-07-12 21:26 UTCVendor advisory
  50. 2026-07-12 21:26 UTCGHSA enrichment
  51. 2026-07-12 17:45 UTCEG score recompute
  52. 2026-07-12 17:45 UTCVendor advisory
  53. 2026-07-12 17:45 UTCGHSA enrichment
  54. 2026-07-12 14:04 UTCEG score recompute
  55. 2026-07-12 14:04 UTCVendor advisory
  56. 2026-07-12 14:03 UTCGHSA enrichment
  57. 2026-07-12 10:21 UTCEG score recompute
  58. 2026-07-12 10:21 UTCVendor advisory
  59. 2026-07-12 10:21 UTCGHSA enrichment
  60. 2026-07-12 06:39 UTCEG score recompute
  61. 2026-07-12 06:39 UTCVendor advisory
  62. 2026-07-12 06:39 UTCGHSA enrichment
  63. 2026-07-12 05:43 UTCEPSS rescore
  64. 2026-07-12 05:43 UTCEPSS rescore
  65. 2026-07-12 02:58 UTCEG score recompute
  66. 2026-07-12 02:58 UTCVendor advisory
  67. 2026-07-12 02:58 UTCGHSA enrichment
  68. 2026-07-11 23:17 UTCEG score recompute
  69. 2026-07-11 23:17 UTCVendor advisory
  70. 2026-07-11 23:17 UTCGHSA enrichment
  71. 2026-07-11 19:36 UTCEG score recompute
  72. 2026-07-11 19:36 UTCVendor advisory
  73. 2026-07-11 19:36 UTCGHSA enrichment
  74. 2026-07-11 15:55 UTCEG score recompute
  75. 2026-07-11 15:55 UTCVendor advisory

Publicly available exploits

(3 references)

Working exploit code is in the public domain (2 GitHub PoCs) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-49864
    First seen May 13, 2021

    Firefox 72 IonMonkey - JIT Type Confusion

    Open source ↗
  • GitHub PoClsw29475/CVE-2019-17026
    First seen Feb 24, 2021
    Open source ↗
  • GitHub PoCmaxpl0it/CVE-2019-17026-Exploit
    First seen Aug 27, 2020

    An exploit for CVE-2019-17026. It pops xcalc and was tested on Ubuntu (x64).

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(6)

What is CVE-2019-17026?
CVE-2019-17026 is a high vulnerability published on March 2, 2020. Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.
When was CVE-2019-17026 disclosed?
CVE-2019-17026 was first published in the National Vulnerability Database on March 2, 2020, with the most recent update on November 4, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2019-17026 actively exploited?
Yes. CISA added CVE-2019-17026 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Mozilla Firefox and Thunderbird. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2019-17026?
CVE-2019-17026 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2019-17026?
CVE-2019-17026 affects Mozilla Firefox and Thunderbird. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2019-17026?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-17026, 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

Explore the affected products and dependency analysis for CVE-2019-17026

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