CVE-2021-30657: Apple macOS Unspecified Vulnerability

How to check if you are exposed to CVE-2021-30657

1. Find every Apple macOS system you or your clients run, including ones exposed to the internet. Those come first: CISA only lists flaws attackers are already using.
2. Compare each version with the fixed versions in the vendor advisory. Where no fix exists yet, apply the vendor’s mitigation or take the system off the internet.
3. Run a credentialed vulnerability scan to catch the systems you missed, then check that the next scan no longer reports CVE-2021-30657.

US federal agencies had to fix this by 2021-11-17. Everyone else should treat that deadline as a guide: if it has passed, this is overdue.

Timeline

1. 2021-11-03 · Added to CISA's Known Exploited Vulnerabilities catalog
2. 2021-11-17 · Fix-by date for US federal agencies, passed 1,810 days ago

Weakness type

• CWE-862

More exploited Apple vulnerabilities

CISA lists 95 exploited Apple vulnerabilities. The closest matches:

• CVE-2026-65400Apple macOS Improper Authentication VulnerabilityAdded 2026-08-18
• CVE-2019-8526Apple macOS Use-After-Free VulnerabilityAdded 2023-04-17
• CVE-2022-22675Apple macOS Out-of-Bounds Write VulnerabilityAdded 2022-04-04
• CVE-2022-22674Apple macOS Out-of-Bounds Read VulnerabilityAdded 2022-04-04
• CVE-2021-30713Apple macOS Unspecified VulnerabilityAdded 2021-11-03
• CVE-2026-86950Apple Multiple Products Out-of-Bounds Write VulnerabilityAdded 2026-09-29
• CVE-2025-43520Apple Multiple Products Classic Buffer Overflow VulnerabilityAdded 2026-03-20
• CVE-2025-43510Apple Multiple Products Improper Locking VulnerabilityAdded 2026-03-20

Keep going

• All exploited CVEs
• Check another CVE
• What is CISA KEV?
• What is EPSS?

Sources: CISA Known Exploited Vulnerabilities catalog (version 2026.10.30); EPSS data from FIRST.org; CVSS and descriptions from the NIST National Vulnerability Database. Checked 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.