# CVE-2026-87766: Bubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup > Attackers can write files outside the sandbox during setup via symlink traversal, potentially modifying host files or escalating privileges. - **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 9 Sep 2026 - **Updated:** 19 Oct 2026 - **Also known as:** ALSA-2026:85306, ALSA-2026:85308, ALSA-2026:85309, AZL-100908, CLSA-2026-1791475845, DEBIAN-CVE-2026-87766, ECHO-3a6d-2aae-ba82, GHSA-pxhw-h44j-8pfx, MGASA-2026-0371, RHSA-2026:85306, RHSA-2026:85308, RHSA-2026:85309, RHSA-2026:85312, RHSA-2026:85313, RHSA-2026:85317, RHSA-2026:85319, RHSA-2026:85322, RHSA-2026:85324, RHSA-2026:85325, RLSA-2026:85306, RLSA-2026:85308, RLSA-2026:85309, UBUNTU-CVE-2026-87766 ## What is CVE-2026-87766? CVE-2026-87766 is a high-severity path traversal vulnerability in Red Hat Enterprise Linux 10, published on 9 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description 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. Weakness: CWE-59 (Improper Link Resolution Before File Access) ## Which versions are affected by CVE-2026-87766? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `bubblewrap` | AlmaLinux:10 | All versions | 0.10.0-5.el10_2 | | `bubblewrap` | AlmaLinux:8 | All versions | 0.4.0-3.el8_10 | | `bubblewrap` | AlmaLinux:9 | All versions | 0.6.3-1.el9_8.1 | | `bubblewrap` | Red Hat:enterprise_linux:10.2 | All versions | 0:0.10.0-5.el10_2 | | `bubblewrap-debuginfo` | Red Hat:enterprise_linux:10.2 | All versions | 0:0.10.0-5.el10_2 | | `bubblewrap-debugsource` | Red Hat:enterprise_linux:10.2 | All versions | 0:0.10.0-5.el10_2 | | `bubblewrap` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.4.0-3.el8_10 | | `bubblewrap-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.4.0-3.el8_10 | | `bubblewrap-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:0.4.0-3.el8_10 | | `bubblewrap` | Red Hat:enterprise_linux:9::baseos | All versions | 0:0.6.3-1.el9_8.1 | | `bubblewrap-debuginfo` | Red Hat:enterprise_linux:9::baseos | All versions | 0:0.6.3-1.el9_8.1 | | `bubblewrap-debugsource` | Red Hat:enterprise_linux:9::baseos | All versions | 0:0.6.3-1.el9_8.1 | | `bubblewrap` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:0.10.0-3.el10_0.4 | | `bubblewrap-debuginfo` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:0.10.0-3.el10_0.4 | | `bubblewrap-debugsource` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:0.10.0-3.el10_0.4 | | `bubblewrap` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:0.4.0-3.el8_4 | | `bubblewrap-debuginfo` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:0.4.0-3.el8_4 | | `bubblewrap-debugsource` | Red Hat:rhel_aus:8.4::baseos | All versions | 0:0.4.0-3.el8_4 | | `bubblewrap` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:0.4.0-3.el8_6 | | `bubblewrap-debuginfo` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:0.4.0-3.el8_6 | | `bubblewrap-debugsource` | Red Hat:rhel_aus:8.6::baseos | All versions | 0:0.4.0-3.el8_6 | | `bubblewrap` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:0.4.0-3.el8_8 | | `bubblewrap-debuginfo` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:0.4.0-3.el8_8 | | `bubblewrap-debugsource` | Red Hat:rhel_e4s:8.8::baseos | All versions | 0:0.4.0-3.el8_8 | | `bubblewrap` | Red Hat:rhel_e4s:9.2::baseos | All versions | 0:0.4.1-7.el9_2.1 | | `bubblewrap-debuginfo` | Red Hat:rhel_e4s:9.2::baseos | All versions | 0:0.4.1-7.el9_2.1 | | `bubblewrap-debugsource` | Red Hat:rhel_e4s:9.2::baseos | All versions | 0:0.4.1-7.el9_2.1 | | `bubblewrap` | Red Hat:rhel_e4s:9.4::baseos | All versions | 0:0.4.1-7.el9_4.1 | | `bubblewrap-debuginfo` | Red Hat:rhel_e4s:9.4::baseos | All versions | 0:0.4.1-7.el9_4.1 | | `bubblewrap-debugsource` | Red Hat:rhel_e4s:9.4::baseos | All versions | 0:0.4.1-7.el9_4.1 | | `bubblewrap` | Red Hat:rhel_eus:9.6::baseos | All versions | 0:0.4.1-8.el9_6.1 | | `bubblewrap-debuginfo` | Red Hat:rhel_eus:9.6::baseos | All versions | 0:0.4.1-8.el9_6.1 | | `bubblewrap-debugsource` | Red Hat:rhel_eus:9.6::baseos | All versions | 0:0.4.1-8.el9_6.1 | | `bubblewrap` | Red Hat:rhel_eus_long_life:8.4::baseos | All versions | 0:0.4.0-3.el8_4 | | `bubblewrap-debuginfo` | Red Hat:rhel_eus_long_life:8.4::baseos | All versions | 0:0.4.0-3.el8_4 | | `bubblewrap-debugsource` | Red Hat:rhel_eus_long_life:8.4::baseos | All versions | 0:0.4.0-3.el8_4 | | `bubblewrap` | Red Hat:rhel_eus_long_life:8.6::baseos | All versions | 0:0.4.0-3.el8_6 | | `bubblewrap-debuginfo` | Red Hat:rhel_eus_long_life:8.6::baseos | All versions | 0:0.4.0-3.el8_6 | | `bubblewrap-debugsource` | Red Hat:rhel_eus_long_life:8.6::baseos | All versions | 0:0.4.0-3.el8_6 | | `bubblewrap` | Red Hat:rhel_tus:8.8::baseos | All versions | 0:0.4.0-3.el8_8 | ## How do I fix CVE-2026-87766? Upgrade to a fixed version. ## Is CVE-2026-87766 being exploited? There is no known exploitation of CVE-2026-87766 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-87766 and fix it if it is affected. What it is: CVE-2026-87766 is a high-severity path traversal vulnerability in Red Hat Enterprise Linux 10, published on 9 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-87766 in the wild and no public exploit code. Affected product: Red Hat Enterprise Linux 10. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-87766/ (Markdown: https://insights.sbomify.com/CVE-2026-87766/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-87766 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87766 - OSV: https://osv.dev/vulnerability/CVE-2026-87766 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-87766/ Summaries are generated and may contain mistakes; the official description above is the record.