Exploited vulnerability · CISA KEV

Is CVE-2019-11707 exploited? Yes: in CISA KEV since 23 May 2022

Gociux · Mozilla Firefox and Thunderbird · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2019-11707, Mozilla Firefox and Thunderbird Type Confusion Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 23 May 2022, 1035 days after it was published. It affects Mozilla Firefox and Thunderbird. If you run it, CISA's required action is: Apply updates per vendor instructions.

exploitedYesCISA KEV · 23 May 2022

ransomwareNot knownno confirmed use

EPSStop 5%very likely to be exploited

severity8.8CVSS 3.1 · high

US federal due13 Jun 2022BOD 22-01 deadline

What it is

Mozilla Firefox and Thunderbird contain a type confusion vulnerability that can occur when manipulating JavaScript objects due to issues in Array.pop, allowing for an exploitable crash.

Vendor	Mozilla (13 exploited CVEs in KEV)
Product	Firefox and Thunderbird
Vulnerability	Mozilla Firefox and Thunderbird Type Confusion Vulnerability
Weakness	CWE-843
Published	23 Jul 2019
Added to KEV	23 May 2022
Reported by (CNA)	mozilla

What to do

Check whether you run it. Look for Firefox and Thunderbird in your asset inventory, including appliances and cloud images. Stack check lists every exploited Mozilla CVE at once.
Apply the fix. Apply updates per vendor instructions.
If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 23 Jul 2019.
Get told next time. Email alerts when CISA adds a CVE for Mozilla.

Other exploited CVEs in Firefox and Thunderbird

CVE-2019-11708: Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability (23 May 2022)
CVE-2013-1690: Mozilla Firefox and Thunderbird Denial-of-Service Vulnerability (28 Mar 2022)
CVE-2020-6819: Mozilla Firefox And Thunderbird Use-After-Free Vulnerability (3 Nov 2021)
CVE-2020-6820: Mozilla Firefox And Thunderbird Use-After-Free Vulnerability (3 Nov 2021)
CVE-2019-17026: Mozilla Firefox And Thunderbird Type Confusion Vulnerability (3 Nov 2021)

References

nvd.nist.gov/vuln/detail/CVE-2019-11707

Questions

Is CVE-2019-11707 being exploited?

Yes. CISA added CVE-2019-11707 to the Known Exploited Vulnerabilities catalog on 23 May 2022, which means there is reliable evidence of exploitation in the wild.

Is CVE-2019-11707 used in ransomware attacks?

CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.

How do I fix CVE-2019-11707?

Apply updates per vendor instructions. Check Mozilla's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Firefox and Thunderbird and watch it for signs of compromise.

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in May 2022 · Mozilla scorecard · act-now radar.

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