CVE-2021-1871
A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina,…
- Published
- Updated
- Reserved
- Assigned by
- apple
Description
A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability.
- Added
- 3 Nov 2021
- Fix due (US federal)
- 17 Nov 2021
- Used by ransomware
- Not known
Apply updates per vendor instructions.
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
- 4 months later
· 4 months later
Published
- 7 months later
· 7 months 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 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 7.0% · top 5.8% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Weakness
- A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
- CWE-noinfo Not enough information
Affected products
- affected unspecified – < 14.4
- affected unspecified – < 11.2
References (5)
- https://support.apple.com/en-us/HT212147 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212146 (opens in a new tab)x_refsource_MISCx_transferred
- FEDORA-2021-864dc37032 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- DSA-4923 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871 (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)
- 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://trackcve.app/cve/CVE-2021-1871)Record last updated .