CVE-2021-30666

Apple iOS: WebKit Buffer Overflow

As of , CVE-2021-30666 in Apple iOS is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch soon.

Exploited
Yes: CISA listed it on 3 November 2021
US federal deadline
17 November 202114 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.03Higher than 86% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

Apple iOS WebKit contains a buffer-overflow 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.

CISA's description

A buffer overflow issue was addressed with improved memory handling. This issue is fixed in iOS 12.5.3. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

The CVE record's description, from apple

CVE published
8 September 2021
Assigned by
apple
CVSS
8.8 High (CVSS 3.1, from CISA-ADP)
CWE-119
Improper Restriction of Operations within the Bounds of a Memory Buffer
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

iOS: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2016-4657Webkit Memory CorruptionApple iOSPatch this weekMetasploit module; EPSS 0.67; verified Exploit-DB entry0.67
CVE-2016-4655Information DisclosureApple iOSPatch this weekMetasploit module; verified Exploit-DB entry0.33
CVE-2016-4656Memory CorruptionApple iOSPatch this weekMetasploit module; verified Exploit-DB entry0.24
CVE-2021-30761WebKit Memory CorruptionApple iOSPatch soon0.11
CVE-2021-30762WebKit Use-After-FreeApple iOSPatch soon0.11
CVE-2022-42856Type ConfusionApple iOSPatch soon0.09
CVE-2019-7287Memory CorruptionApple iOSPatch soon0.05

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