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Fencer Vulns
high 7.8

CVE-2021-30663 kev in the critical feed json

An integer overflow was addressed with improved input validation.

published 2021-09-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-17580

cvss
7.8
version 3.1, CNA
cisa kev
Exploited
added 2021-11-03
epss
3.5%
EPSS 3.5% chance of exploitation in 30 days, percentile 89%
public exploits
0
none known

Summary

An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution.

Patch / fix

cisa required action Apply updates per vendor instructions.

  • Apple macOS 11.3, 12.5, 14.1, 14.5, 14.6
  • wpewebkit Debian 14, Debian 13, Debian 12 2.32.3-1
  • webkit2gtk Debian 14, Debian 13, Debian 12 2.32.3-1

debian advisories DEBIAN-CVE-2021-30663

  • webkit2gtk Ubuntu 18.04 LTS 2.32.3-0ubuntu0.18.04.1
  • webkit2gtk Ubuntu 20.04 LTS 2.32.3-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2021-30663

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

  • LibRaw RHEL 8 0.19.5-3.el8
  • webkit2gtk3 RHEL 8 2.32.3-2.el8
  • gnome-autoar RHEL 8 0.2.3-2.el8
  • webkit2gtk3-jsc RHEL 8 2.32.3-2.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-2021:4381

  • webkit2gtk3 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +10 more 2.32.3-3.77.3
  • libsoup SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +10 more 2.62.2-17.8.1
  • webkit2gtk3 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.32.3-2.66.1
  • webkit2gtk3 SLE Module for Desktop Applications 15 SP3, SLE Module for Desktop Applications 15 SP2, SLE Module for Basesystem 15 SP3 +1 more 2.32.3-9.1

suse advisories SUSE-SU-2021:2762-1SUSE-SU-2021:2600-1SUSE-SU-2021:2598-1

  • webkit2gtk3 openSUSE Leap 15.2 2.32.3-lp152.2.16.1
  • webkit2gtk3 openSUSE Leap 15.3 2.32.3-9.1

opensuse advisories openSUSE-SU-2021:1101-1openSUSE-SU-2021:2598-1

  • gdm AlmaLinux 8 1:40.0-15.el8
  • gtk3 AlmaLinux 8 3.22.30-8.el8
  • vino AlmaLinux 8 3.22.0-11.el8
  • LibRaw AlmaLinux 8 0.19.5-3.el8
  • mutter AlmaLinux 8 3.32.2-60.el8
  • gnome-shell AlmaLinux 8 3.32.2-40.el8
  • webkit2gtk3 AlmaLinux 8 2.32.3-2.el8
  • gnome-autoar AlmaLinux 8 0.2.3-2.el8

almalinux advisories ALSA-2021:4381

  • gdm Rocky Linux 8 1:40.0-15.el8
  • gtk3 Rocky Linux 8 3.22.30-8.el8
  • vino Rocky Linux 8 3.22.0-11.el8
  • LibRaw Rocky Linux 8 0.19.5-3.el8
  • mutter Rocky Linux 8 3.32.2-60.el8
  • gnome-shell Rocky Linux 8 3.32.2-40.el8
  • webkit2gtk3 Rocky Linux 8 2.32.3-2.el8
  • gnome-autoar Rocky Linux 8 0.2.3-2.el8

rocky linux advisories RLSA-2021:4381

  • webkit2gtk Alpine 3.20, Alpine 3.19, Alpine 3.18 +4 more 2.32.3-r0

alpine advisories ALPINE-CVE-2021-30663

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

  • wpewebkit Arch Linux 2.32.3-1

arch linux advisories AVG-2221

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-2021-30663 updated cvss 8.8

webkitgtk: Integer overflow leading to arbitrary code execution

  • Red Hat Enterprise Linux 6 webkitgtk Red Hat Enterprise Linux 7 webkitgtk3, libwebkit2gtk
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) webkit2gtk3 2.32.3-2.el8, webkit2gtk3-jsc 2.32.3-2.el8
    fixed: vendor fix RHSA-2021:4381
  • 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 2.48.3-2.el7_9, webkitgtk4-jsc 2.48.3-2.el7_9
    fixed: vendor fix RHSA-2025:10364
  • Red Hat CodeReady Linux Builder (v. 8) LibRaw 0.19.5-3.el8, mutter 3.32.2-60.el8, accountsservice 0.6.55-2.el8, gnome-software 3.36.1-10.el8, accountsservice-libs 0.6.55-2.el8 Red Hat Enterprise Linux 9 webkit2gtk3, webkit2gtk3-jsc Red Hat Enterprise Linux AppStream (v. 8) gdm 40.0-15.el8, gtk3 3.22.30-8.el8, vino 3.22.0-11.el8, LibRaw 0.19.5-3.el8, mutter 3.32.2-60.el8, gnome-autoar 0.2.3-2.el8, +41 more Red Hat Enterprise Linux BaseOS (v. 8) gsettings-desktop-schemas 3.32.0-6.el8
    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

Timeline

  1. 0-day patched (Project Zero)
  2. Published
  3. Added to CISA KEV
  4. CISA patch deadline
  5. CISA SSVC: exploitation active

Known exploited

Added
5 y ago
Patch by
2021-11-17 (4 y ago)
Ransomware
Not known
Required action
Apply updates per vendor instructions.
Vendor, product
Apple, Multiple Products
CISA name
Apple Multiple Products WebKit Integer Overflow Vulnerability

Zero-day

Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.

Patched
2021-05-03
Details
project zero tracker

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
total
Assessed
21 mo ago

Exploit prediction

3.52% chance of exploitation in the next 30 days, higher than 89% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 3.1 7.8 CVSS:3.1/AV:L/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 macOS

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

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.