CVE-2023-40548

HIGHNVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 65% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
7.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.4Exploit: NoneExposed: 0

A fix is available — apply it.

A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw causes memory corruption and can lead to a crash or data integrity issues during the boot phase.

CVSS v3
7.4
EG Score
7.4(medium)
EG Risk
33(Track)
EG Risk 33/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity74% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
35.3%
KEV
Not listed

Published

January 29, 2024

Last Modified

June 26, 2026

Advisory Details (10)

Auto-updated Jun 26, 2026
Patch available. Sources: redhat.
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2023-40548
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.6 Extended

https://access.redhat.com/errata/RHSA-2024:2086
redhat Patch Available

Affected: Red Hat Enterprise Linux 7.

https://access.redhat.com/errata/RHSA-2024:1959
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2024:1903
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2024:1902
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.8 Extended

https://access.redhat.com/errata/RHSA-2024:1883
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.2 Extended Update Support.

https://access.redhat.com/errata/RHSA-2024:1876
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support, E4S Red Hat Enterprise Linux 8.4 Update Services for SA

https://access.redhat.com/errata/RHSA-2024:1873
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.0 Extended Update Support.

https://access.redhat.com/errata/RHSA-2024:1835
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.2 Advanced Update Support, Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions, and Red

https://access.redhat.com/errata/RHSA-2024:1834

Vendor Advisories for CVE-2023-40548(9)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(9)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatshim-0:15.8-2.el8_62024-04-29redhat
redhatshim-signed-0:15.8-1.el72024-04-23redhat
redhatshim-unsigned-x64-0:15.8-2.el82024-04-18redhat
redhatshim-0:15.8-4.el9_32024-04-18redhat
redhatshim-0:15.8-2.el8_42024-04-18redhat
redhatshim-0:15.8-4.el8_92024-04-18redhat
redhatshim-0:15.8-3.el9_22024-04-18redhat
redhatshim-0:15.8-2.el8_22024-04-16redhat
redhatshim-unsigned-x64-0:15.8-2.el92024-04-16redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 12× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 110 total refreshes for this CVE.

  1. 2026-07-23 02:25 UTCEG score recompute
  2. 2026-07-22 23:12 UTCEG score recompute▲ 2.50
  3. 2026-07-22 14:06 UTCEPSS rescore
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  16. 2026-07-14 21:25 UTCOSV refresh
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  1. 2026-07-08 15:13 UTCEPSS rescore
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  18. 2026-06-26 22:09 UTCOSV refresh
  19. 2026-06-25 13:48 UTCEPSS rescore
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  45. 2026-06-11 13:59 UTCEPSS rescore
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  50. 2026-06-09 09:30 UTCOSV refresh
  51. 2026-06-08 14:16 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2023-40548?
CVE-2023-40548 is a high vulnerability published on January 29, 2024. A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw…
When was CVE-2023-40548 disclosed?
CVE-2023-40548 was first published in the National Vulnerability Database on January 29, 2024, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-40548 actively exploited?
CVE-2023-40548 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 35.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-40548?
CVE-2023-40548 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2023-40548?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-40548, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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