How severe is CVE-2023-40550?

CVE-2023-40550 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2023-40550 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-40550?

CVE-2023-40550 primarily affects Redhat Shim. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-40550?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2023-40550 have an EU (EUVD) identifier?

Yes. CVE-2023-40550 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-45121.

When was CVE-2023-40550 published?

CVE-2023-40550 was published on 2024-01-29 and last updated on 2026-06-17.

CVE-2023-40550

CVE-2023-40550 is a medium-severity vulnerability in Redhat Shim with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2023-45121
Weakness: CWE-125
Affected product: Redhat Shim
Published: 2024-01-29
Last modified: 2026-06-17

Description

An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue may expose sensitive data during the system's boot phase.

Frequently asked questions

What is CVE-2023-40550?: An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue may expose sensitive data during the system's boot phase.
How severe is CVE-2023-40550?: CVE-2023-40550 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2023-40550 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-40550?: CVE-2023-40550 primarily affects Redhat Shim. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-40550?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-40550 have an EU (EUVD) identifier?: Yes. CVE-2023-40550 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-45121.
When was CVE-2023-40550 published?: CVE-2023-40550 was published on 2024-01-29 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:redhat:shim:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

More vulnerabilities in Redhat Shim

CVE-2023-40547 — High (CVSS 8.3): A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when…
CVE-2014-3677 — High (CVSS 7.5): Unspecified vulnerability in Shim might allow attackers to execute arbitrary code via a crafted MOK list, which…
CVE-2014-3676 — High (CVSS 7.5): Heap-based buffer overflow in Shim allows remote attackers to execute arbitrary code via a crafted IPv6 address,…
CVE-2023-40548 — High (CVSS 7.4): A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a…
CVE-2022-28737 — Medium (CVSS 6.5): There's a possible overflow in handle_image() when shim tries to load and execute crafted EFI executables; The…
CVE-2023-40549 — Medium (CVSS 6.2): An out-of-bounds read flaw was found in Shim due to the lack of proper boundary verification during the load of a PE…

All CVEs affecting Redhat Shim →

Other CWE-125 (Out-of-bounds Read) vulnerabilities

CVE-2026-24826 — Critical (CVSS 10.0): Out-of-bounds Write, Divide By Zero, NULL Pointer Dereference, Use of Uninitialized Resource, Out-of-bounds Read,…
CVE-2024-22004 — Critical (CVSS 10.0): Due to length check, an attacker with privilege access on a Linux Nonsecure operating system can trigger a…
CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

Browse all CWE-125 (Out-of-bounds Read) vulnerabilities →