CVE-2021-1879
This issue was addressed by improved management of object lifetimes. This issue is fixed in iOS 12.5.2, iOS 14.4.2 and iPadOS 14.4.2,…
- Published
- Updated
- Reserved
- Assigned by
- apple
Description
This issue was addressed by improved management of object lifetimes. This issue is fixed in iOS 12.5.2, iOS 14.4.2 and iPadOS 14.4.2, watchOS 7.3.3. Processing maliciously crafted web content may lead to universal cross site scripting. 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 watchOS WebKit Cross-Site Scripting (XSS) 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 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 7.1% · top 5.7% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.
Weakness
- Processing maliciously crafted web content may lead to universal cross site scripting. Apple is aware of a report that this issue may have been actively exploited.
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)All about CWE-79 and its CVEs
Affected products
References (4)
- https://support.apple.com/en-us/HT212256 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212257 (opens in a new tab)x_refsource_MISCx_transferred
- https://support.apple.com/en-us/HT212258 (opens in a new tab)x_refsource_MISCx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1879 (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-2021-1879)Record last updated .