What is CVE-2020-27930?

CVE-2020-27930 is a high-severity vulnerability in Apple iOS And Ipados, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2020-12-08.

How severe is CVE-2020-27930?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2020-27930 known to be exploited?

Yes. CVE-2020-27930 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 8 public proof-of-concept repositories are indexed.

Buffer overflow in Apple iOS And Ipados

CVE-2020-27930

A memory corruption issue was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.1, iOS 12.4.9, watchOS 6.2.9, Security Update 2020-006 High Sierra, Security Update 2020-006 Mojave, iOS 14.2 and iPadOS 14.2, watchOS 5.3.9, macOS Catalina 10.15.7 Supplemental Update, macOS Catalina 10.15.7 Update. Processing a maliciously crafted font may lead to arbitrary code execution.

Vulnerability class: Buffer Overflow

Published 2020-12-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.220 (97.6th percentile), scored 2026-10-18.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.220 · newest: 0.220 · change: 0.000

Affected products

Apple iOS And Ipados — versions unspecified
Apple Ipados
Apple Iphone OS
Apple macOS — versions unspecified
Apple Mac OS X
Apple watchOS — versions unspecified

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

support.apple.com/en-us/HT211931 (Vendor Advisory)
support.apple.com/en-us/HT211928 (Vendor Advisory)
support.apple.com/en-us/HT211929 (Vendor Advisory)
support.apple.com/en-us/HT211940 (Vendor Advisory)
support.apple.com/en-us/HT211944 (Vendor Advisory)
support.apple.com/en-us/HT211945 (Vendor Advisory)
support.apple.com/en-us/HT211946 (Vendor Advisory)
support.apple.com/en-us/HT211947 (Vendor Advisory)
seclists.org/fulldisclosure/2020/Dec/32 (mailing-list, Mailing List, Third Party Advisory)
packetstormsecurity.com/files/161294/Apple-Safari-Remote-Code-Execution.html (VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2020-27930?: CVE-2020-27930 is a high-severity vulnerability in Apple iOS And Ipados, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2020-12-08.
How severe is CVE-2020-27930?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2020-27930 known to be exploited?: Yes. CVE-2020-27930 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 8 public proof-of-concept repositories are indexed.