CVE-2021-30737
Published: April 11, 2026
Official Description
A memory corruption issue in the ASN.1 decoder was addressed by removing the vulnerable code. This issue is fixed in tvOS 14.6, Security Update 2021-004 Mojave, iOS 14.6 and iPadOS 14.6, iOS 12.5.4, Security Update 2021-003 Catalina, macOS Big Sur 11.4, watchOS 7.5. Processing a maliciously crafted certificate may lead to arbitrary code execution.
Risk Analysis
This memory corruption flaw in Apple's ASN.1 decoder could allow an attacker to execute arbitrary code by processing a specially crafted certificate. Given its presence in CISA's KEV catalog, this vulnerability is actively exploited and represents a critical risk.
This vulnerability is actively exploited in the wild and is included in CISA's KEV catalog, confirming its real-world impact. Exploitation can occur through processing a maliciously crafted certificate.
To mitigate this risk, update Apple devices to tvOS 14.6, Security Update 2021-004 Mojave, iOS 14.6 and iPadOS 14.6, iOS 12.5.4, Security Update 2021-003 Catalina, macOS Big Sur 11.4, or watchOS 7.5. Prompt patching is essential.
Technical Analysis
CVE-2021-30737 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-30737 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-30737 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1