Answer in brief
CVE-2023-40548 records a High severity (CVSS 7.4) vulnerability in Shim: interger overflow leads to heap buffer overflow in verify_sbat_section on 32-bits systems. The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2023-40548 records a High severity (CVSS 7.4) vulnerability in Shim: interger overflow leads to heap buffer overflow in verify_sbat_section on 32-bits systems. The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Published upstream
Jan 29, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 26, 2026
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.
Quoted source text, attributed separately from HOL analysis.
CVSS is 7.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Published upstream
Jan 29, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 26, 2026
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.
Quoted source text, attributed separately from HOL analysis.