CVE-2021-30666 (GCVE-0-2021-30666)
Vulnerability from cvelistv5 – Published: 2021-09-08 14:25 – Updated: 2025-10-21 23:25- 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.
- CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer
| URL | Tags |
|---|---|
| https://support.apple.com/en-us/HT212341 | x_refsource_MISC |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
Exploited: Yes
Timestamps
Scope
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-119 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | iOS |
| Due Date | 2021-11-17 |
| Date Added | 2021-11-03 |
| Vendorproject | Apple |
| Vulnerabilityname | Apple iOS WebKit Buffer Overflow Vulnerability |
| Knownransomwarecampaignuse | Unknown |
References
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
Exploited: Yes
Timestamps
Scope
Evidence
Type: Public Report
Signal: Successful Exploitation
Confidence: 70%
Source: kevintel
Details
| Feed | KEVIntel (kevintel.com) |
|---|---|
| Title | A buffer overflow issue was addressed with improved memory handling. This issue is fixed in iOS 12.5.3. Processing maliciously crafted web content... |
| Vendor | Apple |
| Product | iOS |
| Added Date | 2021-11-03T00:00:00.000Z |
| Cvss Score | 8.8 |
| Epss Score | None |
| Cvss Severity | HIGH |
| Epss Percentile | None |
| Used In Malware | unknown |
| Ahead Of Cisa Kev | None |
| Not Yet In Cisa Kev | False |
References
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"reference_data": [
{
"name": "https://support.apple.com/en-us/HT212341",
"refsource": "MISC",
"url": "https://support.apple.com/en-us/HT212341"
}
]
}
}
}
},
"cveMetadata": {
"assignerOrgId": "286789f9-fbc2-4510-9f9a-43facdede74c",
"assignerShortName": "apple",
"cveId": "CVE-2021-30666",
"datePublished": "2021-09-08T14:25:25.000Z",
"dateReserved": "2021-04-13T00:00:00.000Z",
"dateUpdated": "2025-10-21T23:25:34.810Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1"
}
}
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.