Exploited vulnerability · CISA KEV

Is CVE-2021-30665 exploited? Yes: in CISA KEV since 3 Nov 2021

Gociux · Apple Multiple Products · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2021-30665, Apple Multiple Products WebKit Memory Corruption Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 3 Nov 2021, 56 days after it was published. It affects Apple Multiple Products. If you run it, CISA's required action is: Apply updates per vendor instructions.

exploitedYesCISA KEV · 3 Nov 2021

ransomwareNot knownno confirmed use

EPSSbelow top 10%lower predicted activity right now (it is still confirmed exploited)

severity8.8CVSS 3.1 · high

US federal due17 Nov 2021BOD 22-01 deadline

What it is

Apple iOS, iPadOS, macOS, watchOS, and tvOS WebKit contain a memory corruption vulnerability that leads to code execution when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.

Vendor	Apple (96 exploited CVEs in KEV)
Product	Multiple Products
Vulnerability	Apple Multiple Products WebKit Memory Corruption Vulnerability
Weakness	CWE-787
Published	8 Sep 2021
Added to KEV	3 Nov 2021
Reported by (CNA)	apple

What to do

Check whether you run it. Look for Multiple Products in your asset inventory, including appliances and cloud images. Stack check lists every exploited Apple 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 8 Sep 2021.
Get told next time. Email alerts when CISA adds a CVE for Apple.

Other exploited CVEs in Multiple Products

CVE-2024-27834: Apple Multiple Products Improper Authentication Vulnerability (4 Nov 2026)
CVE-2026-86950: Apple Multiple Products Out-of-Bounds Write Vulnerability (29 Sep 2026)
CVE-2025-43510: Apple Multiple Products Improper Locking Vulnerability (20 Mar 2026)
CVE-2025-43520: Apple Multiple Products Classic Buffer Overflow Vulnerability (20 Mar 2026)
CVE-2025-31277: Apple Multiple Products Buffer Overflow Vulnerability (20 Mar 2026)
CVE-2023-43000: Apple Multiple products Use-After-Free Vulnerability (5 Mar 2026)

References

nvd.nist.gov/vuln/detail/CVE-2021-30665

Questions

Is CVE-2021-30665 being exploited?

Yes. CISA added CVE-2021-30665 to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, which means there is reliable evidence of exploitation in the wild.

Is CVE-2021-30665 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-2021-30665?

Apply updates per vendor instructions. Check Apple's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Multiple Products 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 November 2021 · Apple scorecard · act-now radar.

Running Apple in a regulated environment?

We check exposure across your estate, patch or mitigate with your team, and set up detection for what attackers do after exploiting it.

Get in touch →