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Fencer Vulns
high 8.8

CVE-2020-9951 json

A use after free issue was addressed with improved memory management.

published 2020-10-16 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-30730

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

A use after free issue was addressed with improved memory management. This issue is fixed in Safari 14.0. Processing maliciously crafted web content may lead to arbitrary code execution.

Patch / fix

  • Apple Safari Safari 14.0
  • wpewebkit Debian 14, Debian 13, Debian 12 2.30.0-1
  • webkit2gtk Debian 14, Debian 13, Debian 12 2.30.1-1

debian advisories DEBIAN-CVE-2020-9951

  • webkit2gtk Ubuntu 18.04 LTS 2.30.3-0ubuntu0.18.04.1
  • webkit2gtk Ubuntu 20.04 LTS 2.30.3-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2020-9951

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

  • gdm RHEL 8 1:3.28.3-39.el8
  • glib2 RHEL 8 2.56.4-9.el8
  • glib2-fam RHEL 8 2.56.4-9.el8
  • glib2-tests RHEL 8 2.56.4-9.el8
  • webkit2gtk3 RHEL 8 2.30.4-1.el8
  • webkit2gtk3-jsc RHEL 8 2.30.4-1.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-2021:1586

  • 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
  • webkit2gtk3 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.32.1-2.63.3
  • webkit2gtk3 SLE Module for Desktop Applications 15 SP2, SLE Module for Basesystem 15 SP2 2.30.3-3.9.3
  • webkit2gtk3 SLES for SAP 15, SLES 15-LTSS, SLE Module for Desktop Applications 15 SP1 +3 more 2.30.3-3.63.2

suse advisories SUSE-SU-2022:0182-2SUSE-SU-2022:0183-1SUSE-SU-2022:0182-1SUSE-SU-2022:0142-1SUSE-SU-2021:1990-1SUSE-SU-2020:3867-1

  • webkit2gtk3 openSUSE Leap 15.3 2.34.3-23.3
  • webkit2gtk3 openSUSE Leap 15.2 2.30.3-lp152.2.7.3
  • webkit2gtk3 openSUSE Leap 15.1 2.30.3-lp151.2.28.2

opensuse advisories openSUSE-SU-2022:0182-1openSUSE-SU-2020:2310-1openSUSE-SU-2020:2304-1

  • gjs AlmaLinux 8 1.56.2-5.el8
  • gtk2 AlmaLinux 8 2.24.32-5.el8
  • gvfs AlmaLinux 8 1.36.2-11.el8
  • vala AlmaLinux 8 0.40.19-2.el8
  • atkmm AlmaLinux 8 2.24.2-7.el8
  • gamin AlmaLinux 8 0.1.10-32.el8
  • woff2 AlmaLinux 8 1.0.2-5.el8
  • cairomm AlmaLinux 8 1.12.0-8.el8

almalinux advisories ALSA-2021:1586

  • gdm Rocky Linux 8 1:3.28.3-39.el8
  • gjs Rocky Linux 8 1.56.2-5.el8
  • gtk2 Rocky Linux 8 2.24.32-5.el8
  • gvfs Rocky Linux 8 1.36.2-11.el8
  • vala Rocky Linux 8 0.40.19-2.el8
  • atkmm Rocky Linux 8 2.24.2-7.el8
  • gamin Rocky Linux 8 0.1.10-32.el8
  • woff2 Rocky Linux 8 1.0.2-5.el8

rocky linux advisories RLSA-2021:1586

  • webkit2gtk Alpine 3.20, Alpine 3.19, Alpine 3.18 +5 more 2.30.0-r0

alpine advisories ALPINE-CVE-2020-9951

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-2020-9951 updated cvss 8.8

webkitgtk: use-after-free may lead 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 2.30.4-1.el8, webkit2gtk3-jsc 2.30.4-1.el8
    fixed: vendor fix RHSA-2021:1586
  • 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 CodeReady Linux Builder (v. 8) gvfs 1.36.2-11.el8, vala 0.40.19-2.el8, libsass 3.4.5-6.el8, libdazzle 3.28.5-2.el8, libepubgen 0.1.0-3.el8, nautilus 3.28.1-15.el8 Red Hat Enterprise Linux AppStream (v. 8) gjs 1.56.2-5.el8, gdm 3.28.3-39.el8, woff2 1.0.2-5.el8, atkmm 2.24.2-7.el8, gtk2 2.24.32-5.el8, gvfs 1.36.2-11.el8, +71 more Red Hat Enterprise Linux BaseOS (v. 8) glib2 2.56.4-9.el8, gamin 0.1.10-32.el8, glib2-fam 2.56.4-9.el8, glib2-tests 2.56.4-9.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

2.33% chance of exploitation in the next 30 days, higher than 83% 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 Safari

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.