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Fencer Intel
medium 5.3

CVE-2021-42762 json

BubblewrapLauncher.cpp in WebKitGTK and WPE WebKit before 2.34.1 allows a limited sandbox bypass that allows a sandboxed process to trick h…

published 5y ago modified 4mo ago also EUVD-2021-29720

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

BubblewrapLauncher.cpp in WebKitGTK and WPE WebKit before 2.34.1 allows a limited sandbox bypass that allows a sandboxed process to trick host processes into thinking the sandboxed process is not confined by the sandbox, by abusing VFS syscalls that manipulate its filesystem namespace. The impact is limited to host services that create UNIX sockets that WebKit mounts inside its sandbox, and the sandboxed process remains otherwise confined. NOTE: this is similar to CVE-2021-41133.

Patch / fix

  • webkitgtk webkitgtk 2.34.1
  • wpewebkit wpe_webkit 2.34.1
  • 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-2021-42762

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

ubuntu advisories UBUNTU-CVE-2021-42762

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

  • 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-2025:10364

  • webkit2gtk3 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 2.34.1-3.87.1
  • webkit2gtk3 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.32.4-2.74.5
  • webkit2gtk3 SLE Module for Desktop Applications 15 SP3, SLE Module for Desktop Applications 15 SP2, SLE Module for Basesystem 15 SP3 +1 more 2.32.4-15.1

suse advisories SUSE-SU-2021:3769-1SUSE-SU-2021:3768-1SUSE-SU-2021:3603-1

  • webkit2gtk3 openSUSE Leap 15.2 2.32.4-lp152.2.22.1
  • webkit2gtk3 openSUSE Leap 15.3 2.32.4-15.1

opensuse advisories openSUSE-SU-2021:1454-1openSUSE-SU-2021:3603-1

  • webkit2gtk Alpine 3.20, Alpine 3.19, Alpine 3.18 +3 more 2.34.1-r0

alpine advisories ALPINE-CVE-2021-42762

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 2.34.1-1

arch linux advisories AVG-2484

Is CVE-2021-42762 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2021-42762 updated cvss 5.3

webkitgtk: limited sandbox escape via VFS syscalls

  • 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 6 webkitgtk Red Hat Enterprise Linux 7 webkitgtk3, libwebkit2gtk Red Hat Enterprise Linux 8 webkit2gtk3, webkit2gtk3-jsc, webkit2gtk3-plugin-process-gtk2 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

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugs.webkit.org https://bugs.webkit.org/show_bug.cgi?id=231479 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

References

Sources

Fencer Intel 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.