Known exploited vulnerability
CVE-2021-30952
The short answer
CVE-2021-30952 affects Apple watchOS and is rated high (CVSS 7.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-03-05: attackers are using it, so patch it first.
What it is
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.
Weakness: CWE-190.
Severity
7.8 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since Mar 5, 2026
Federal due date Mar 26, 2026
EPSS, next 30 days
7.0%
Higher than 94% of scored CVEs
How it can be exploited
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected products
watchOS, iOS and iPadOS, macOS. NVD's record lists the exact affected versions.
References
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7EQVZ3CEMTINLBZ7PBC7WRXVEVCRHNSM/ Broken Link
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HQKWD4BXRDD2YGR5AVU7H5J5PIQIEU6V/ Broken Link
- support.apple.com/en-us/HT212975 Release NotesVendor Advisory
- support.apple.com/en-us/HT212976 Release NotesVendor Advisory
- support.apple.com/en-us/HT212978 Release NotesVendor Advisory
- support.apple.com/en-us/HT212980 Release NotesVendor Advisory
- support.apple.com/en-us/HT212982 Release NotesVendor Advisory
- www.debian.org/security/2022/dsa-5060 Mailing ListThird Party Advisory
- www.debian.org/security/2022/dsa-5061 Mailing ListThird Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7EQVZ3CEMTINLBZ7PBC7WRXVEVCRHNSM/ Broken Link
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HQKWD4BXRDD2YGR5AVU7H5J5PIQIEU6V/ Broken Link
- support.apple.com/en-us/HT212975 Release NotesVendor Advisory
Questions
Is CVE-2021-30952 being exploited?
Yes. CISA added CVE-2021-30952 to its Known Exploited Vulnerabilities catalog on 2026-03-05, with a federal remediation due date of 2026-03-26.
How do I fix CVE-2021-30952?
CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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