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Fencer Vulns
high 8.8

CVE-2021-30818 json

A type confusion issue was addressed with improved state handling.

published 2021-10-28 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-17735

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

A type confusion issue was addressed with improved state handling. This issue is fixed in iOS 14.8 and iPadOS 14.8, tvOS 15, iOS 15 and iPadOS 15, Safari 15, watchOS 8. Processing maliciously crafted web content may lead to arbitrary code execution.

Patch / fix

  • Apple iOS and iPadOS 14.8, 15
  • Apple tvOS 15
  • Apple Safari 15
  • Apple watchOS 8
  • wpewebkit Debian 14, Debian 13, Debian 12 2.34.1-1
  • webkit2gtk Debian 14, Debian 13, Debian 12 2.34.1-1

debian advisories DEBIAN-CVE-2021-30818

  • webkit2gtk Ubuntu 20.04 LTS 2.34.1-0ubuntu0.20.04.1
  • webkit2gtk Ubuntu 22.04 LTS 2.34.0-1ubuntu1

ubuntu advisories UBUNTU-CVE-2021-30818

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • webkit2gtk3 RHEL 8 2.34.6-1.el8
  • webkit2gtk3-jsc RHEL 8 2.34.6-1.el8
  • webkitgtk4 RHEL 7 ELS 2.48.3-2.el7_9
  • webkitgtk4-jsc RHEL 7 ELS 2.48.3-2.el7_9

red hat advisories RHSA-2025:10364RHSA-2022:1777

  • webkit2gtk3 SLES 15 SP2-BCL, SLE Real Time 15 SP2, SLE Module for Desktop Applications 15 SP3 +9 more 2.34.3-23.3
  • webkit2gtk3 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 2.34.3-3.92.1
  • webkit2gtk3 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.34.3-2.82.1

suse advisories SUSE-SU-2022:0182-2SUSE-SU-2022:0183-1SUSE-SU-2022:0182-1SUSE-SU-2022:0142-1

  • webkit2gtk3 openSUSE Leap 15.3 2.34.3-23.3

opensuse advisories openSUSE-SU-2022:0182-1

  • webkit2gtk3 AlmaLinux 8 2.34.6-1.el8
  • webkit2gtk3-jsc AlmaLinux 8 2.34.6-1.el8

almalinux advisories ALSA-2022:1777

  • webkit2gtk3 Rocky Linux 8 2.34.6-1.el8

rocky linux advisories RLSA-2022:1777

  • webkit2gtk Alpine 3.20, Alpine 3.19, Alpine 3.18 +2 more 2.34.0-r0

alpine advisories ALPINE-CVE-2021-30818

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-30818 updated cvss 8.8

webkitgtk: Type confusion issue leading to arbitrary code execution

  • Red Hat Enterprise Linux 6 webkitgtk Red Hat Enterprise Linux 7 webkitgtk3, libwebkit2gtk
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) webkit2gtk3 2.34.6-1.el8, webkit2gtk3-jsc 2.34.6-1.el8
    fixed: vendor fix RHSA-2022:1777
  • Red Hat Enterprise Linux Server (v. 7 ELS) webkitgtk4 2.48.3-2.el7_9, webkitgtk4-jsc 2.48.3-2.el7_9 Red Hat Enterprise Linux Server Optional (v. 7 ELS) webkitgtk4-doc 2.48.3-2.el7_9, webkitgtk4-devel 2.48.3-2.el7_9, webkitgtk4-debuginfo 2.48.3-2.el7_9, webkitgtk4-jsc-devel 2.48.3-2.el7_9
    fixed: vendor fix RHSA-2025:10364
  • Red Hat Enterprise Linux 9 webkit2gtk3, webkit2gtk3-jsc
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.62% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Apple iOS and iPadOS
  • Apple tvOS
  • Apple Safari
  • Apple watchOS

Classification

Weakness
  • CWE-843 Access of Resource Using Incompatible Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.