CVE-2019-17026Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted…
- 8.8HighCVSS base score
- 46.3%Exploitation in 30 daysEPSS · top 1.2% of all CVEs
- YesKnown exploitedin CISA's KEV since 3 Nov 2021
- 1Public exploitsMetasploit, Nuclei and Exploit-DB
Description
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Mozilla Firefox And Thunderbird Type Confusion Vulnerability.
- Added
- 3 Nov 2021
- Fix due (US federal)
- 3 May 2022
- Used by ransomware
- Not known
Apply updates per vendor instructions.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 3 Nov 2021.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list an Exploit-DB entry for it. CISA's SSVC rates its exploitation: it is being exploited.
Show the exploits1
Exploit-DB1 entry
- Firefox 72 IonMonkey - JIT Type Confusion (Exploit-DB entry) (opens in a new tab)
EDB-ID 49864local, windows_x86-64published 13 May 2021Not verified
Modules, templates and exploits as listed by the Metasploit Framework (BSD-3-Clause), ProjectDiscovery's Nuclei templates (MIT) and the Exploit Database (GPLv2), read once a day. Where the data comes from
Timeline
ID reserved
By mozilla
- 5 months later
· 5 months later
Published
- 20 months later
· 20 months later
Added to CISA KEV
Known exploited in the wild
- 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 |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 46.3% · top 1.2% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Affected products
- affected unspecified – < 68.4.1
- affected unspecified – < 68.4.1
- affected unspecified – < 72.0.1
References
References7
- https://www.mozilla.org/security/advisories/mfsa2020-04/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2020-03/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1607443 (opens in a new tab)x_refsource_MISCx_transferred
- GLSA-202003-02 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- USN-4335-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- http://packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.html (opens in a new tab)x_refsource_MISCx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-17026 (opens in a new tab)government-resource
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)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2019-7500 (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-2019-17026)Record last updated .