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Fencer Intel
high 8.8

CVE-2026-87766 json

Bubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup

published 2mo ago modified 15h ago also EUVD-2026-74778 , GHSA-pxhw-h44j-8pfx

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository containers/bubblewrap. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

A flaw was found in bubblewrap. During sandbox setup, creating files or directories under the new root can follow a parent symlink onto the host via /oldroot, writing attacker-chosen paths outside the sandbox as the launching user. This happens before the sandboxed process starts. This issue is GHSA-pxhw-h44j-8pfx. It is fixed in bubblewrap 0.12.0.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:0.10.0-5.el10_2
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:0.10.0-3.el10_0.4
  • Red Hat Red Hat Enterprise Linux 8 0:0.4.0-3.el8_10
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:0.4.0-3.el8_4
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:0.4.0-3.el8_4
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:0.4.0-3.el8_6
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 0:0.4.0-3.el8_6
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:0.4.0-3.el8_8
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:0.4.0-3.el8_8
  • Red Hat Red Hat Enterprise Linux 9 0:0.6.3-1.el9_8.1, 0:0.6.3-1.el9_9.1
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:0.4.1-7.el9_2.1
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:0.4.1-7.el9_4.1
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:0.4.1-8.el9_6.1
  • bubblewrap Debian 13 0.12.0-1~deb13u1
  • bubblewrap Debian 14 0.12.0-1

debian advisories DEBIAN-CVE-2026-87766

  • bubblewrap RHEL 10.2 0.10.0-5.el10_2
  • bubblewrap RHEL 9 0.6.3-1.el9_8.1
  • bubblewrap RHEL 8 0.4.0-3.el8_10
  • bubblewrap RHEL 9.6 EUS 0.4.1-8.el9_6.1
  • bubblewrap RHEL 9.2 E4S 0.4.1-7.el9_2.1
  • bubblewrap RHEL 8.6 EUS_LONG_LIFE, RHEL 8.6 AUS 0.4.0-3.el8_6
  • bubblewrap RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 0.4.0-3.el8_4
  • bubblewrap RHEL 9.4 E4S 0.4.1-7.el9_4.1

red hat advisories RHSA-2026:85325RHSA-2026:85322RHSA-2026:85324RHSA-2026:85317RHSA-2026:85319RHSA-2026:85312

  • flatpak openSUSE Tumbleweed 1.18.3-1.1

opensuse advisories openSUSE-SU-2026:11873-1

  • bubblewrap AlmaLinux 8 0.4.0-3.el8_10
  • bubblewrap AlmaLinux 10 0.10.0-5.el10_2
  • bubblewrap AlmaLinux 9 0.6.3-1.el9_8.1

almalinux advisories ALSA-2026:85306ALSA-2026:85308ALSA-2026:85309

  • bubblewrap Rocky Linux 9 0.6.3-1.el9_8.1
  • bubblewrap Rocky Linux 10 0.10.0-5.el10_2
  • bubblewrap Rocky Linux 8 0.4.0-3.el8_10

rocky linux advisories RLSA-2026:98521RLSA-2026:85308RLSA-2026:85309RLSA-2026:85306

  • bubblewrap Azure Linux 3.0 0.12.0-1

azure linux advisories AZL-100908

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-87766 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.

Check with Fencer

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-2026-87766 updated cvss 8.8

bubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup

  • Red Hat Enterprise Linux BaseOS (v. 8) bubblewrap 0.4.0-3.el8_10
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85306
  • Red Hat Enterprise Linux BaseOS (v. 9) bubblewrap 0.6.3-1.el9_8.1, bubblewrap 0.6.3-1.el9_9.1
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85309
  • Red Hat Enterprise Linux BaseOS (v. 10) bubblewrap 0.10.0-5.el10_2
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85308
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bubblewrap 0.4.0-3.el8_4
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85317
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bubblewrap 0.4.0-3.el8_6
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85324
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) bubblewrap 0.4.0-3.el8_8
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85313
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bubblewrap 0.4.1-7.el9_2.1
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85322
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bubblewrap 0.4.1-7.el9_4.1
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85319
show 6 more
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) bubblewrap 0.10.0-3.el10_0.4
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85312
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) bubblewrap 0.4.1-8.el9_6.1
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85325
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bubblewrap 0.4.0-3.el8_4
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85317
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bubblewrap 0.4.0-3.el8_6
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85324
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) bubblewrap 0.4.0-3.el8_8
    fixed: vendor fix “Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.” RHSA-2026:85313
  • Red Hat Hardened Images bubblewrap
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Red Hat Hardened Images

Classification

Weakness
  • CWE-59 Improper Link Resolution Before File Access

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.

The maintainers of containers/bubblewrap published their own advisory on GitHub. Reviewed sources take precedence over it.