Answer in brief
CVE-2021-30666 records a High severity vulnerability in CVE Program Container. The current sources mark it as known exploited. The current feed maps Apple/iOS (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. Known-exploitation status makes exposure review time-sensitive. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Apple/iOS (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Apple/iOSgeneric | >=unspecified <12.5 | 12.5 |
Published upstream
Sep 8, 2021
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2025
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
May 24, 2026
Added to CISA KEV
Nov 3, 2021
Evidence: source:kev:kev:kev:recordA 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..
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-30666 records a High severity vulnerability in CVE Program Container. The current sources mark it as known exploited. The current feed maps Apple/iOS (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. Known-exploitation status makes exposure review time-sensitive. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Apple/iOS (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Apple/iOSgeneric | >=unspecified <12.5 | 12.5 |
Published upstream
Sep 8, 2021
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2025
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
May 24, 2026
Added to CISA KEV
Nov 3, 2021
Evidence: source:kev:kev:kev:recordA 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..
Quoted source text, attributed separately from HOL analysis.