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Full vulnerability report · 2023
CVE-2023-2640High confidence

Canonical Ubuntu Kernel — Incorrect Authorization

Canonical · Ubuntu Kernel

7.8HighCVSS 3.1
Recommended action
Within 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

6 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivelinux-aws-6.14Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-gcp-6.14Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-hwe-6.14Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oem-6.14Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-oracle-6.14Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-34106

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → Incorrect Authorization → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-863

CWE-863: Incorrect Authorization. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-863Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2023-1903Ubuntu Linux: Mehrere Schwachstellen

Ein lokaler Angreifer kann mehrere Schwachstellen im Ubuntu Linux Kernel ausnutzen, um Sicherheitsvorkehrungen zu umgehen und seine Rechte zu erhöhen.

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0787Multiples vulnérabilités dans le noyau Linux d'Ubuntu

ntation). Documentation Bulletin de sécurité Ubuntu USN-8426-2 du 16 juin 2026 https://ubuntu.com/security/notices/USN-8426-2 Bulletin de sécurité Ubuntu USN-8439-1 du 16 juin 2026 https://ubuntu.com/security/notices/USN-8439-1 Bulletin de sécurité Ubuntu USN-8440-1 du 16 juin 2026 https://ubuntu.com/security/notices/USN-8440-1 Bulletin de sécurité Ubuntu USN-8361-3 du 17 juin 2026 https://ubuntu.com/security/notices/USN-8361-3 Bulletin de sécurité Ubuntu USN-8390-2 du 17 juin 2026 https://ubuntu.com/security/notices/USN-8390-2 Bulletin de sécurité Ubuntu USN-8441-1 du 17 juin 2026 https://ubuntu.com/security/notices/USN-8441-1 Référence CVE CVE-2023-2640 https://www.cve.org/CVERecord?id=CVE-2023-2640 Référence CVE CVE-2023-32629 https://www.cve.org/CVERecord?id=CVE-2023-32629 Référence CVE CVE-2024-35862 https://www.cve.org/CVERecord?id=CVE-2024-35862 Référence CVE CVE-2024-36347 https://www.cve.org/CVERecord?id=CVE-2024-36347 Référence CVE CVE-2024-50004 https://www.cve.org/CVERecord?id=CVE-2024-50004 Référence CVE CVE-2024-50060 https://www.cve.org/CVERecord?id=CVE-2024-50060 Référence CVE CVE-2024-57795 https://www.cve.org/CVERecord?id=CVE-2024-57795 Référence CVE CVE-2024-58096 https://www.cve.org/CVERecord?id=CVE-2024-58096 Référence CVE CVE-2024-58097 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0663Multiples vulnérabilités dans le noyau Linux d'Ubuntu

m/security/notices/USN-8291-3 Bulletin de sécurité Ubuntu USN-8296-2 du 25 mai 2026 https://ubuntu.com/security/notices/USN-8296-2 Bulletin de sécurité Ubuntu USN-8305-1 du 25 mai 2026 https://ubuntu.com/security/notices/USN-8305-1 Bulletin de sécurité Ubuntu USN-8278-2 du 26 mai 2026 https://ubuntu.com/security/notices/USN-8278-2 Bulletin de sécurité Ubuntu USN-8280-3 du 26 mai 2026 https://ubuntu.com/security/notices/USN-8280-3 Bulletin de sécurité Ubuntu USN-8305-2 du 26 mai 2026 https://ubuntu.com/security/notices/USN-8305-2 Bulletin de sécurité Ubuntu USN-8310-1 du 26 mai 2026 https://ubuntu.com/security/notices/USN-8310-1 Référence CVE CVE-2023-2640 https://www.cve.org/CVERecord?id=CVE-2023-2640 Référence CVE CVE-2023-32629 https://www.cve.org/CVERecord?id=CVE-2023-32629 Référence CVE CVE-2023-53421 https://www.cve.org/CVERecord?id=CVE-2023-53421 Référence CVE CVE-2023-53520 https://www.cve.org/CVERecord?id=CVE-2023-53520 Référence CVE CVE-2023-53662 https://www.cve.org/CVERecord?id=CVE-2023-53662 Référence CVE CVE-2023-54207 https://www.cve.org/CVERecord?id=CVE-2023-54207 Référence CVE CVE-2024-35862 https://www.cve.org/CVERecord?id=CVE-2024-35862 Référence CVE CVE-2024-50004 https://www.cve.org/CVERecord?id=CVE-2024-50004 Référence CVE CVE-2024-50060 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0638Multiples vulnérabilités dans le noyau Linux d'Ubuntu

i 2026 https://ubuntu.com/security/notices/USN-8278-1 Bulletin de sécurité Ubuntu USN-8279-1 du 19 mai 2026 https://ubuntu.com/security/notices/USN-8279-1 Bulletin de sécurité Ubuntu USN-8280-1 du 19 mai 2026 https://ubuntu.com/security/notices/USN-8280-1 Bulletin de sécurité Ubuntu USN-8281-1 du 19 mai 2026 https://ubuntu.com/security/notices/USN-8281-1 Bulletin de sécurité Ubuntu USN-8289-1 du 20 mai 2026 https://ubuntu.com/security/notices/USN-8289-1 Bulletin de sécurité Ubuntu USN-8291-1 du 21 mai 2026 https://ubuntu.com/security/notices/USN-8291-1 Référence CVE CVE-2022-49033 https://www.cve.org/CVERecord?id=CVE-2022-49033 Référence CVE CVE-2023-2640 https://www.cve.org/CVERecord?id=CVE-2023-2640 Référence CVE CVE-2023-32629 https://www.cve.org/CVERecord?id=CVE-2023-32629 Référence CVE CVE-2023-53421 https://www.cve.org/CVERecord?id=CVE-2023-53421 Référence CVE CVE-2023-53520 https://www.cve.org/CVERecord?id=CVE-2023-53520 Référence CVE CVE-2023-53662 https://www.cve.org/CVERecord?id=CVE-2023-53662 Référence CVE CVE-2023-54207 https://www.cve.org/CVERecord?id=CVE-2023-54207 Référence CVE CVE-2024-27388 https://www.cve.org/CVERecord?id=CVE-2024-27388 Référence CVE CVE-2024-35862 https://www.cve.org/CVERecord?id=CVE-2024-35862 Référence CVE CVE-2024-49938 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0602Multiples vulnérabilités dans le noyau Linux d'Ubuntu

i 2026 https://ubuntu.com/security/notices/USN-8200-3 Bulletin de sécurité Ubuntu USN-8254-2 du 11 mai 2026 https://ubuntu.com/security/notices/USN-8254-2 Bulletin de sécurité Ubuntu USN-8255-2 du 11 mai 2026 https://ubuntu.com/security/notices/USN-8255-2 Bulletin de sécurité Ubuntu USN-8265-1 du 11 mai 2026 https://ubuntu.com/security/notices/USN-8265-1 Bulletin de sécurité Ubuntu USN-8266-1 du 11 mai 2026 https://ubuntu.com/security/notices/USN-8266-1 Bulletin de sécurité Ubuntu USN-8267-1 du 11 mai 2026 https://ubuntu.com/security/notices/USN-8267-1 Référence CVE CVE-2022-49046 https://www.cve.org/CVERecord?id=CVE-2022-49046 Référence CVE CVE-2023-2640 https://www.cve.org/CVERecord?id=CVE-2023-2640 Référence CVE CVE-2023-32629 https://www.cve.org/CVERecord?id=CVE-2023-32629 Référence CVE CVE-2023-53421 https://www.cve.org/CVERecord?id=CVE-2023-53421 Référence CVE CVE-2023-53520 https://www.cve.org/CVERecord?id=CVE-2023-53520 Référence CVE CVE-2023-53662 https://www.cve.org/CVERecord?id=CVE-2023-53662 Référence CVE CVE-2023-54207 https://www.cve.org/CVERecord?id=CVE-2023-54207 Référence CVE CVE-2024-27388 https://www.cve.org/CVERecord?id=CVE-2024-27388 Référence CVE CVE-2024-36347 https://www.cve.org/CVERecord?id=CVE-2024-36347 Référence CVE CVE-2024-46777 https://www.cve.org/CVERecord?id=C

Official advisory
CERT-FR · French · CERTFR-2023-AVI-0663Multiples vulnérabilités dans le noyau Linux d'Ubuntu

ve.org/CVERecord?id=CVE-2023-1855 Référence CVE CVE-2023-1990 https://www.cve.org/CVERecord?id=CVE-2023-1990 Référence CVE CVE-2023-2002 https://www.cve.org/CVERecord?id=CVE-2023-2002 Référence CVE CVE-2023-2124 https://www.cve.org/CVERecord?id=CVE-2023-2124 Référence CVE CVE-2023-2163 https://www.cve.org/CVERecord?id=CVE-2023-2163 Référence CVE CVE-2023-2194 https://www.cve.org/CVERecord?id=CVE-2023-2194 Référence CVE CVE-2023-2235 https://www.cve.org/CVERecord?id=CVE-2023-2235 Référence CVE CVE-2023-2269 https://www.cve.org/CVERecord?id=CVE-2023-2269 Référence CVE CVE-2023-23004 https://www.cve.org/CVERecord?id=CVE-2023-23004 Référence CVE CVE-2023-2640 https://www.cve.org/CVERecord?id=CVE-2023-2640 Référence CVE CVE-2023-28466 https://www.cve.org/CVERecord?id=CVE-2023-28466 Référence CVE CVE-2023-2898 https://www.cve.org/CVERecord?id=CVE-2023-2898 Référence CVE CVE-2023-30772 https://www.cve.org/CVERecord?id=CVE-2023-30772 Référence CVE CVE-2023-3111 https://www.cve.org/CVERecord?id=CVE-2023-3111 Référence CVE CVE-2023-31248 https://www.cve.org/CVERecord?id=CVE-2023-31248 Référence CVE CVE-2023-3141 https://www.cve.org/CVERecord?id=CVE-2023-3141 Référence CVE CVE-2023-32248 https://www.cve.org/CVERecord?id=CVE-2023-32248 Référence CVE CVE-2023-32254 https://www.cve.org/CVERecord?id=CVE-202

Official advisory
CERT-FR · French · CERTFR-2023-AVI-0599Multiples vulnérabilités dans le noyau Linux d'Ubuntu

.org/CVERecord?id=CVE-2023-1859 Référence CVE CVE-2023-1990 https://www.cve.org/CVERecord?id=CVE-2023-1990 Référence CVE CVE-2023-1998 https://www.cve.org/CVERecord?id=CVE-2023-1998 Référence CVE CVE-2023-21106 https://www.cve.org/CVERecord?id=CVE-2023-21106 Référence CVE CVE-2023-2124 https://www.cve.org/CVERecord?id=CVE-2023-2124 Référence CVE CVE-2023-2162 https://www.cve.org/CVERecord?id=CVE-2023-2162 Référence CVE CVE-2023-25012 https://www.cve.org/CVERecord?id=CVE-2023-25012 Référence CVE CVE-2023-2513 https://www.cve.org/CVERecord?id=CVE-2023-2513 Référence CVE CVE-2023-2612 https://www.cve.org/CVERecord?id=CVE-2023-2612 Référence CVE CVE-2023-2640 https://www.cve.org/CVERecord?id=CVE-2023-2640 Référence CVE CVE-2023-26545 https://www.cve.org/CVERecord?id=CVE-2023-26545 Référence CVE CVE-2023-2860 https://www.cve.org/CVERecord?id=CVE-2023-2860 Référence CVE CVE-2023-2985 https://www.cve.org/CVERecord?id=CVE-2023-2985 Référence CVE CVE-2023-30456 https://www.cve.org/CVERecord?id=CVE-2023-30456 Référence CVE CVE-2023-3090 https://www.cve.org/CVERecord?id=CVE-2023-3090 Référence CVE CVE-2023-3111 https://www.cve.org/CVERecord?id=CVE-2023-3111 Référence CVE CVE-2023-31248 https://www.cve.org/CVERecord?id=CVE-2023-31248 Référence CVE CVE-2023-3141 https://www.cve.org/CVERecord?id=CVE-2023-3

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
See the vendor and CVE records for the affected range.
Fixed
Ubuntu Kernel: < 6.2.0-26.26, < 6.0.0-1020.20, < 5.4.0-155.172
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 26 Jul 2023 · Last source change 23 Oct 2024, 14:59 UTC · CWE-863 · Incorrect Authorization

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-34106
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-2640 · cve.blacktree.nl