kernel: overlayfs: In Ubuntu skip permission checking for trusted.overlayfs.* xattrs
Published Jul 26, 2023
7.8
HIGHCVSS 3.1
EPSS 15.20%
Description
On Ubuntu kernels carrying both c914c0e27eb0 and "UBUNTU: SAUCE: overlayfs: Skip permission checking for trusted.overlayfs.* xattrs", an unprivileged user may set privileged extended attributes on the mounted files, leading them to be set on the upper files without the appropriate security checks.
Affected products
No data.
- 23.04
-
- Version 0StatusaffectedConstraints<5.4.0-155.172
- Version 0StatusaffectedConstraints<6.0.0-1020.20
- Version 0StatusaffectedConstraints<6.2.0-26.26
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Canonical | Ubantu Kernel | n/a |
|
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise Linux 8
kernel-rt
Not affected
Red Hat Enterprise Linux 9
kernel
Not affected
Red Hat Enterprise Linux 9
kernel-rt
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 9 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | n/a |
No package ranges for this CVE.
Remediation
Vendor solution
If not needed, disable the ability for unprivileged users to create namespaces. To do this temporarily, do: sudo sysctl -w kernel.unprivileged_userns_clone=0 To disable across reboots, do: echo kernel.unprivileged_userns_clone=0 | \ sudo tee /etc/sysctl.d/99-disable-unpriv-userns.conf
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
NoTechnical Impact
TotalDecision
n/aAssessed Oct 23, 2024 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2023–2026- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (22 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 15.20% (0.15199) | 96.66th | v5 (v2026.06.15) |
| Jun 15, 2026 | 15.78% (0.15783) | 96.44th | v5 (v2026.06.15) |
| Nov 21, 2025 | 91.87% (0.91874) | 99.67th | v4 (v2025.03.14) |
| Nov 18, 2025 | 65.65% (0.65651) | 98.50th | v4 (v2025.03.14) |
| Apr 15, 2025 | 91.92% (0.91919) | 99.67th | v4 (v2025.03.14) |
| Mar 30, 2025 | 64.76% (0.64757) | 98.32th | v4 (v2025.03.14) |
| Mar 29, 2025 | 52.09% (0.52094) | 96.95th | v4 (v2025.03.14) |
| Mar 28, 2025 | 65.16% (0.65160) | 98.34th | v4 (v2025.03.14) |
| Mar 27, 2025 | 44.49% (0.44486) | 97.12th | v4 (v2025.03.14) |
| Mar 24, 2025 | 51.15% (0.51151) | 97.65th | v4 (v2025.03.14) |
| Mar 23, 2025 | 44.49% (0.44486) | 97.17th | v4 (v2025.03.14) |
| Mar 20, 2025 | 51.15% (0.51151) | 97.67th | v4 (v2025.03.14) |
| Mar 19, 2025 | 44.49% (0.44486) | 97.17th | v4 (v2025.03.14) |
| Mar 17, 2025 | 51.15% (0.51151) | 97.61th | v4 (v2025.03.14) |
| Mar 16, 2025 | 1.28% (0.01284) | 85.92th | v3 (v2023.03.01) |
| Dec 12, 2024 | 0.28% (0.00277) | 69.08th | v3 (v2023.03.01) |
| May 21, 2024 | 0.16% (0.00164) | 52.86th | v3 (v2023.03.01) |
| Mar 13, 2024 | 0.23% (0.00232) | 60.61th | v3 (v2023.03.01) |
| Dec 12, 2023 | 0.17% (0.00174) | 54.41th | v3 (v2023.03.01) |
| Nov 17, 2023 | 0.20% (0.00199) | 57.70th | v3 (v2023.03.01) |
| Aug 4, 2023 | 0.05% (0.00047) | 14.35th | v3 (v2023.03.01) |
| Jul 26, 2023 | 0.04% (0.00045) | 12.33th | v3 (v2023.03.01) |
References (10)
- https://access.redhat.com/security/cve/CVE-2023-2640 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2229734 Issue Tracking
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2640 issue-trackingThird Party Advisory
- https://lists.ubuntu.com/archives/kernel-team/2023-July/140920.html
- https://lists.ubuntu.com/archives/kernel-team/2023-July/140923.html mailing-listMailing ListPatch
- https://nvd.nist.gov/vuln/detail/CVE-2023-2640
- https://ubuntu.com/security/notices/USN-6250-1 vendor-advisoryVendor Advisory
- https://wiz.io/blog/ubuntu-overlayfs-vulnerability technical-descriptionExploitMitigationThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2023-2640
- https://www.wiz.io/blog/ubuntu-overlayfs-vulnerability
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2023-2640 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2229734 | Issue Tracking | |
| https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2640 | issue-trackingThird Party Advisory | |
| https://lists.ubuntu.com/archives/kernel-team/2023-July/140920.html | ||
| https://lists.ubuntu.com/archives/kernel-team/2023-July/140923.html | mailing-listMailing ListPatch | |
| https://nvd.nist.gov/vuln/detail/CVE-2023-2640 | ||
| https://ubuntu.com/security/notices/USN-6250-1 | vendor-advisoryVendor Advisory | |
| https://wiz.io/blog/ubuntu-overlayfs-vulnerability | technical-descriptionExploitMitigationThird Party Advisory | |
| https://www.cve.org/CVERecord?id=CVE-2023-2640 | ||
| https://www.wiz.io/blog/ubuntu-overlayfs-vulnerability |
Change history (0)
No recorded changes yet.