Background exploitation KEV catalog No authentication

CVE-2021-1871

Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability

CheckOps priority index

5.9/10 Patch within 7 days

Severity9.8

Probability0.7

Exploitation3/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 7.0% higher than 94.2% of CVEs

CVSS 3.1 9.8 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:

Exploited for 1,826 days 03 Nov 2021

CISA due date 17 Nov 2021 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 3 / 5

KEV catalog (CISA)03 Nov 2021
Exploited in EUVD (ENISA)03 Nov 2021
Used by ransomwareno
EPSS above 10 %7.0%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

Affected products

macOSiOS and iPadOSiOS, iPadOS, and macOS

Affected versions

unspecified <11.2
unspecified <14.4

Weaknesses (CWE)

CWE-1173

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

02 Apr 2021
Published
03 Nov 2021
Exploitation reported (ENISA)
03 Nov 2021
Added to the KEV catalog
17 Nov 2021
CISA remediation due date

References

Other exploited vulnerabilities from the same vendor

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CVE-2023-43000Apple Multiple products Use-After-Free Vulnerability
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