Security readout for executives and security teams
Plain-English summary
Ubuntu shipped EDK II with a default that allowed the UEFI Shell, creating a way for an attacker already resident on the OS to bypass Secure Boot. This is not a remote entry point, but it can weaken a core boot-trust control on affected systems.
Executive priority
Treat as a moderate-priority hardening and trust-chain issue. It is not described as remotely exploitable or actively exploited, but it can undermine Secure Boot after privileged compromise, which matters for sensitive endpoints, servers, and virtualized environments.
Technical view
CVE-2023-48733 is a CWE-1188 insecure-default issue in Canonical Ubuntu EDK II edk2. The source bundle says UEFI Shell remained enabled, allowing an OS-resident attacker to bypass Secure Boot. CVSS 3.1 is 6.7 with local access, low complexity, high privileges, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most relevant where Ubuntu EDK II edk2 is used with Secure Boot expectations. The bundle lists Canonical Ubuntu EDK II, package edk2, version 0, but does not provide a full platform matrix or fixed-version list.
Exploitation context
The provided data does not show active exploitation, and KEV is false. Exploitation requires local OS residency and high privileges, so this is mainly a post-compromise Secure Boot bypass risk rather than an initial access vulnerability.
Researcher notes
Key evidence is limited to the insecure UEFI Shell default and Secure Boot bypass impact. The bundle does not include exploit details, fixed Ubuntu package versions, or proof of exploitation. Validation should stay focused on edk2 presence, Secure Boot reliance, and Canonical guidance.
Mitigation direction
- Check Canonical Ubuntu guidance for affected edk2 builds and fixed versions.
- Apply vendor-provided edk2 updates when available for affected Ubuntu environments.
- Limit administrative access on systems relying on Secure Boot.
- Review virtualized firmware images that use Ubuntu EDK II.
- Track the referenced Launchpad bugs for configuration or release guidance.
Validation and detection
- Inventory Ubuntu systems and images using the edk2 package.
- Confirm whether Secure Boot depends on Ubuntu EDK II in those environments.
- Compare installed edk2 versions against Canonical advisories.
- Check vulnerability management tools for CVE-2023-48733 detection coverage.
- Document any exceptions where fixed versions are not yet identified.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-1188: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-48733 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://bugs.launchpad.net/ubuntu/+source/edk2/+bug/2040137CVE reference · issue-tracking
- https://nvd.nist.gov/vuln/detail/CVE-2023-48733CVE reference · issue-tracking
- https://www.openwall.com/lists/oss-security/2024/02/14/4CVE reference · mailing-list
- https://bugs.launchpad.net/ubuntu/+source/lxd/+bug/2040139CVE reference · issue-tracking
- https://lists.debian.org/debian-lts-announce/2024/06/msg00028.htmlCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Initialization of a Resource with an Insecure Default
Initialization of a Resource with an Insecure Default represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.