Skip to content
Fencer Vulns
high 8.8

CVE-2021-21806 json

An exploitable use-after-free vulnerability exists in WebKitGTK browser version 2.30.3 x64.

published 2021-07-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8978

cvss
8.8
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

An exploitable use-after-free vulnerability exists in WebKitGTK browser version 2.30.3 x64. A specially crafted HTML web page can cause a use-after-free condition, resulting in remote code execution. The victim needs to visit a malicious web site to trigger the vulnerability.

Patch / fix

  • wpewebkit Debian 14, Debian 13, Debian 12 2.30.6-1
  • webkit2gtk Debian 14, Debian 13, Debian 12 2.30.6-1

debian advisories DEBIAN-CVE-2021-21806

  • webkit2gtk Ubuntu 18.04 LTS 2.30.6-0ubuntu0.18.04.1
  • webkit2gtk Ubuntu 20.04 LTS 2.30.6-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2021-21806

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 SLE Module for Desktop Applications 15 SP3, SLE Module for Desktop Applications 15 SP2, SLE Module for Basesystem 15 SP3 +1 more 2.32.4-12.3
  • webkit2gtk3 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.32.4-2.71.2
  • webkit2gtk3 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 2.32.4-3.82.1

suse advisories SUSE-SU-2021:3353-1SUSE-SU-2021:3296-1SUSE-SU-2021:3282-1

  • gtk3 openSUSE Tumbleweed 2.32.4-1.1
  • webkit2gtk3 openSUSE Leap 15.2 2.32.4-lp152.2.19.1
  • webkit2gtk3 openSUSE Leap 15.3 2.32.4-12.3

opensuse advisories openSUSE-SU-2024:11506-1openSUSE-SU-2021:1369-1openSUSE-SU-2021:3353-1

  • 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 2.30.6-r0

alpine advisories ALPINE-CVE-2021-21806

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 2.30.6-1

arch linux advisories AVG-2215

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-2021-21806 updated cvss 8.8

webkitgtk: Use-after-free in fireEventListeners 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 2.32.3-2.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

Exploit prediction

2.83% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • talosintelligence.com https://talosintelligence.com/vulnerability_reports/TALOS-2020-1214 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 8.8 CVSS:3.0/AV:N/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
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • n/a Webkit

Classification

Weakness

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.