Threat Intelligence / CVE / CVE-2021-30952

CVE-2021-30952 — Apple Safari

CISA KEV
CVSS v3.1 7.8 (HIGH) · EPSS 1.2% (higher than 79.3% of all scored CVEs) · Priority 9/10 · Published 2021-08-24

As of 2026-03-06, CVE-2021-30952 is a HIGH-severity vulnerability in Apple Safari, CVSS v3.1 7.8, EPSS 1.2% (79.3th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-05), with a US federal remediation deadline of 2026-03-26. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2021-30952, most recently “Coruna iOS Exploit Kit — 23 Exploits Across 5 Chains Targeting iOS 13-17.2.1 (CVE-2021-30952, CVE-2023-41974, CVE-2023-43000 + 20 More)”.

Last updated: 2026-03-06

What is CVE-2021-30952?

An integer overflow was addressed with improved input validation. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.

The record classifies CVE-2021-30952 under weakness class CWE-190. Its CVSS v3 base vector states that the flaw requires local access to the host, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 12 affected-product entries are recorded, across 5 vendors, listed below. The identifier was first published 1846 days ago.

Severity and exploitation probability

CVSS v3.1 base score
7.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (FIRST)
1.2% probability of exploitation in the next 30 days, higher than 79.3% of all scored CVEs
CISA KEV
Listed since 2026-03-05, federal remediation deadline 2026-03-26
Threadlinqs priority
9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published
2021-08-24, last modified 2026-03-06

Is CVE-2021-30952 being exploited?

CISA added CVE-2021-30952 to the Known Exploited Vulnerabilities catalog on 2026-03-05, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-03-26 under BOD 22-01. It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2021-30952

The record marks a vendor fix as available for CVE-2021-30952. Patch reference: https://support.apple.com/en-us/HT212976. Vendor advisory: https://support.apple.com/en-us/HT212975. Because CVE-2021-30952 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-03-26. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2021-30952

1 tracked threat in the Threadlinqs corpus references CVE-2021-30952, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2021-30952 are available via the Threadlinqs MCP server (Purple tier). View plans →

← all vulnerabilities · Markdown version · Threadlinqs Intelligence