CVE-2020-9934
CVE-2020-9934 is a security flaw in Apple iOS, iPadOS, and macOS, the software on Apple’s iPhones, iPads and Macs. Attackers are using a flaw in Apple iOS, iPadOS, and macOS that its maker hasn't described in detail. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 8 Sep 2022.[1]
Apple iOS, iPadOS, and macOS is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version iOS 13.6 and iPadOS 13.6 and macOS Catalina 10.15.6.
Description
CISA calls it an input validation in Apple iOS, iPadOS, and macOS. In its words: “Apple iOS, iPadOS, and macOS contain an unspecified vulnerability involving input validation which can allow a local attacker to view sensitive user information.”[1]
The CVE record adds: “An issue existed in the handling of environment variables. This issue was addressed with improved validation. This issue is fixed in iOS 13.6 and iPadOS 13.6, macOS Catalina 10.15.6. A local user may be able to view sensitive user information.”[2]
It scores 5.5 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| iOS | iOS 13.6 and iPadOS 13.6 |
| macOS | macOS Catalina 10.15.6 |
Every device with Apple iOS, iPadOS, and macOS needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 8 Sep 2022, 692 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 29 Sep 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 3%. That’s in the top 12% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Apple has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Apple iOS, iPadOS, and macOS now.On iPhone and iPad: Settings, General, Software Update. On a Mac: System Settings, General, Software Update. Install it on every Apple device in the house. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on iOS 13.6 and iPadOS 13.6 or later.Fixed in version iOS 13.6 and iPadOS 13.6 and macOS Catalina 10.15.6. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 5.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 3%.[4] |
See also
Other Apple iOS, iPadOS, and macOS flaws
- CVE-2025-43300: out-of-bounds write ·
- CVE-2023-41064: imageIO buffer overflow ·
- CVE-2023-28206: iOSurfaceAccelerator out-of-bounds write ·
- CVE-2021-30900: out-of-bounds write ·
- CVE-2022-32917: remote code execution ·
- CVE-2022-22620: webkit use-after-free ·
Other Apple flaws
- CVE-2026-86950, Apple devices: out-of-bounds write ·
- CVE-2026-65400, Apple macOS: improper authentication ·
- CVE-2025-43520, Apple devices: classic buffer overflow ·
- CVE-2025-43510, Apple devices: improper locking ·
- CVE-2025-31277, Apple devices: buffer overflow ·
Similar flaws
- CVE-2026-118527, Ivanti Connect Secure: generation of predictable numbers or identifiers ·
- CVE-2026-46300, Linux Kernel: missing initialization of a variable ·
- CVE-2026-41709, Broadcom VMware ESX: insufficient logging ·
- CVE-2026-96656, Plex Media Server: external control of file name or path ·
- CVE-2026-96654, Plex Media Server: improper neutralization of encoded URI schemes in a web page ·
Added the same day
- CVE-2022-3075, Chrome and other Chromium browsers: insufficient data validation ·
- CVE-2022-27593, QNAP Photo Station: externally controlled reference ·
- CVE-2022-26258, D-Link DIR-820L: remote code execution ·
- CVE-2018-7445, MikroTik RouterOS: stack-based buffer overflow ·
- CVE-2018-6530, D-Link Multiple Routers: OS command injection ·
Every Apple flaw on CISA’s list · Everything added in September 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Apple iOS, iPadOS, and macOS Input Validation Vulnerability”. Known Exploited Vulnerabilities Catalog, added 8 Sep 2022.
- ^ National Institute of Standards and Technology. “CVE-2020-9934 Detail”. National Vulnerability Database, published 16 Oct 2020.
- ^ Apple. Advisories and fixes: support.apple.com, support.apple.com, support.apple.com, support.apple.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.032, percentile 88.2, 31 Oct 2026.
- CVE Program. “CVE-2020-9934”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.