CVE-2021-30663An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS…
- 7.8HighCVSS base score
- 3.5%Exploitation in 30 daysEPSS · top 11% of all CVEs
- YesKnown exploitedin CISA's KEV since 3 Nov 2021
- YesPublic exploitsa reference or SSVC says so
Description
An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Apple Multiple Products WebKit Integer Overflow Vulnerability.
- Added
- 3 Nov 2021
- Fix due (US federal)
- 17 Nov 2021
- Used by ransomware
- Not known
Apply updates per vendor instructions.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 3 Nov 2021.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By apple
- 5 months later
· 5 months later
Published
- 56 days later
· 56 days later
Added to CISA KEV
Known exploited in the wild
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 3.5% · top 11% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
References
References6
- https://support.apple.com/en-us/HT212532 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212534 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212341 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212335 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212336 (opens in a new tab)x_refsource_MISCx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30663 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-17580 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-30663)Record last updated .