CVE-2021-1879
MediumExploitedPublic exploitThis issue was addressed by improved management of object lifetimes.
Published Oct 13, 2021 · Updated Oct 21, 2025
Key Facts
Patch immediately- CVE-2021-1879 is a medium-severity vulnerability (CVSS 6.1 v3.1) affecting Ipados (Apple), Iphone OS (Apple), watchOS (Apple) and 2 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 26, 2021. Public exploit code is available.
- EPSS estimates a 7.1% probability of exploitation in the next 30 days.
- Fixed versions are available, including Ipados 14.4.2, Iphone OS 12.5.2, watchOS 7.3.3.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS (30-day exploit likelihood)
7.1%
Higher than 94.1% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-1879 brief as a PDF
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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..
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | Nov 17, 2021 | Not reported |
| Industry KEV feed | Mar 26, 2021 | Nov 17, 2021 | Not reported |
| CIRCL KEV | Nov 3, 2021 | Nov 17, 2021 | Not reported |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
6 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| IpadosApple | See advisory | 14.4.2 |
| Iphone OSApple | See advisory | 12.5.2 |
| watchOSApple | >= unspecified | 7.3.3 |
| iOS | >= unspecified | 12.5 |
| iOS and iPadOS | >= unspecified | 14.4 |
Patched Releases
Ipados
14.4.2
Iphone OS
12.5.2
watchOS
7.3.3, 7.3
iOS
12.5
iOS and iPadOS
14.4
Timeline
Added to Industry KEV feed
Mar 26, 2021
Publicly disclosed
Oct 13, 2021
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Oct 21, 2025
Weakness Type
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
References
- advisoryhttp://feedproxy.google.com/~r/TheHackersNews/~3/elwYiDkfEBM/apple-releases-urgent-iphone-and-ipad.html
- advisoryhttp://feedproxy.google.com/~r/TheHackersNews/~3/xR_aHfkOkh4/apple-issues-urgent-patch-update-for.html
- advisoryhttps://isc.sans.edu/
- advisoryhttps://isc.sans.edu/diary/rss/27250
- advisoryhttps://saaramar.github.io/IOMFB_integer_overflow_poc/
FAQ
Common Questions.
This issue was addressed by improved management of object lifetimes.
Affected: Ipados (Apple); Iphone OS (Apple); watchOS (Apple) versions >= unspecified, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 26, 2021.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of Nov 17, 2021.
Public exploit code is available.
Fixed versions are available, including Ipados 14.4.2, Iphone OS 12.5.2, watchOS 7.3.3.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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