CVE-2021-1883

What it is

This issue was addressed with improved checks. This issue is fixed in Security Update 2021-004 Mojave, iOS 14.5 and iPadOS 14.5, watchOS 7.4, Security Update 2021-003 Catalina, tvOS 14.5, macOS Big Sur 11.3. Processing maliciously crafted server messages may lead to heap corruption.

At a glance

Exploitability

Can be exploited locally on the machine without logging in, but needs a user to act. High risk of data tampering.

Exploit odds

2.0% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-09-08 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:32 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.0% in the next 30 days (EPSS).
• Severity: 5.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-09-08 15:15 UTC

Last modified

2026-06-17 03:32 UTC

Exploit probability

2.0% · EPSS, next 30 days

Weakness

CWE-787 · Out-of-bounds write

Record status

Modified

Affected

• Apple Ipados < 14.5
• Apple Iphone Os < 14.5
• Apple Mac Os X ≤ 10.14.5
• Apple Mac Os X ≤ 10.15.5
• Apple Mac Os X 10.14.6
• Apple Mac Os X 10.15.6
• Apple Mac Os X 10.15.7
• Apple macOS < 11.3

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-1883.md and follow it. Check whether this project is affected by CVE-2021-1883. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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