PatchTheCVECVE-2021-30858: Apple iOS, iPadOS, macOS Use-After-Free Vulnerability
85
Patch now
HIGH 8.8EXPLOITEDWATCHLISTUPGRADEUPGRADEUPGRADE
CVE-2021-30858 is a high-severity flaw (CVSS 8.8) affecting ipados, iphone os, macos, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6. 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.
Why this priority
- High severity
- EPSS top 4%: very likely to be exploited
- Exploited in the wild (CISA KEV)
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.8 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 13.4% (top 4%) |
| CISA exploited list | Yes, fix due 2021-11-17 |
| Weakness | CWE-416 |
| Published | 2021-08-24 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Exploited Added to the CISA Known Exploited Vulnerabilities list
- Deadline CISA due date for US federal agencies to patch
- Updated Record last modified
apple ipados UPGRADE
Affected: >= 13.1 and < 14.8
Fixed in: 14.8
Safe to downgrade to: a release before 13.1
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
apple iphone os UPGRADE
Affected: < 12.5.5 · >= 13.0 and < 14.8
Fixed in: 12.5.5, 14.8
Safe to downgrade to: a release before 13.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
apple macos UPGRADE
Affected: < 11.6
Fixed in: 11.6
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
fedoraproject fedora MITIGATE
Affected: 33 · 34
Fixed in: no fixed release known
Safe to downgrade to: a release before 33
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
debian debian linux MITIGATE
Affected: 10.0 · 11.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 10.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Exact fixes by distribution
A distro patch exists: prefer upgrading over downgrading.
Fedora 46 · bitcoin-core-selinux · FIXED · 0.3-2.fc46 · FEDORA-2026-51fc806272 · source
sudo dnf upgrade --advisory=FEDORA-2026-51fc806272
Fedora ELN · guestfs-tools · FIXED · 1.57.5-1.eln159 · FEDORA-2026-9577c5ec16 · source
sudo dnf upgrade --advisory=FEDORA-2026-9577c5ec16
Ubuntu 20.04 · webkit2gtk · FIXED · 2.32.4-0ubuntu0.20.04.1
sudo apt update && sudo apt install --only-upgrade webkit2gtk
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.32.4-0ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 22.04 · webkit2gtk · NOT AFFECTED
Ubuntu 24.04 · webkit2gtk · NOT AFFECTED
Debian 12 · webkit2gtk · FIXED · 2.32.4-1
sudo apt update && sudo apt install --only-upgrade webkit2gtk
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.32.4-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · webkit2gtk · FIXED · 2.32.4-1
sudo apt update && sudo apt install --only-upgrade webkit2gtk
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.32.4-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · wpewebkit · FIXED · 2.32.4-1
sudo apt update && sudo apt install --only-upgrade wpewebkit
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' wpewebkit)" ge "2.32.4-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · wpewebkit · FIXED · 2.32.4-1
sudo apt update && sudo apt install --only-upgrade wpewebkit
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' wpewebkit)" ge "2.32.4-1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 7 · webkitgtk4 · FIXED · webkitgtk4-2.28.2-3.el7
sudo dnf upgrade --advisory=RHSA-2022:0059
rpm -q webkitgtk4
RHEL 8 · webkit2gtk3 · FIXED · webkit2gtk3-2.30.4-3.el8_4
sudo dnf upgrade --advisory=RHSA-2021:4097
rpm -q webkit2gtk3
RHEL 8.1 Extended Update Support · webkit2gtk3 · FIXED · webkit2gtk3-2.24.4-4.el8_1
sudo dnf upgrade --advisory=RHSA-2021:4686
rpm -q webkit2gtk3
RHEL 8.2 Extended Update Support · webkit2gtk3 · FIXED · webkit2gtk3-2.24.4-4.el8_2
sudo dnf upgrade --advisory=RHSA-2022:0075
rpm -q webkit2gtk3
RHEL 6 · webkitgtk · NO FIX YET
Alpine 3.20 · webkit2gtk · FIXED · webkit2gtk-2.32.4-r0
apk add --upgrade webkit2gtk
apk info -v webkit2gtk
sudo yum update --advisory=ALAS2-2022-1747
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: kmeps4/CVEREV3 (1 stars)
- GitHub PoC: Jeromeyoung/ps4_8.00_vuln_poc (0 stars)
Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-30858?
ipados: upgrade to 14.8; iphone os: upgrade to 12.5.5, 14.8; macos: upgrade to 11.6. Exact commands for each OS are on this page.
Is CVE-2021-30858 being exploited?
Yes. CVE-2021-30858 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.
What does CVE-2021-30858 affect?
CVE-2021-30858 affects ipados, iphone os, macos. Severity is high (CVSS 8.8). A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a
How urgent is CVE-2021-30858?
Priority 85/100. High severity; EPSS top 4%: very likely to be exploited; Exploited in the wild (CISA KEV); On your watchlist
Software pages
Debian vulnerabilities · iOS vulnerabilities · macOS vulnerabilities · iPadOS vulnerabilities
Related CVEs
- CVE-2026-86987 MEDIUM 5.5 UPGRADE UPGRADE An authorization issue was addressed with improved entitlement checks
- CVE-2023-43000 HIGH 8.8 EXPLOITED UPGRADE UPGRADE Apple Multiple products Use-After-Free Vulnerability
- CVE-2023-52356 HIGH 7.5 MITIGATE UPGRADE A segment fault (SEGV) flaw was found in libtiff that could be triggered by passing a crafted tiff file to the
- CVE-2026-86950 HIGH 8.8 EXPLOITED UPGRADE UPGRADE Apple Multiple Products Out-of-Bounds Write Vulnerability
- CVE-2026-65339 MEDIUM 5.0 UPGRADE UPGRADE A logic issue was addressed with improved checks