SARA / Free Tools / CVE / CVE-2023-40547

CVE-2023-40547 — A remote code execution vulnerability was found in Shim

A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitiv

CVSS
8.3 HIGH
EPSS
4.17% (top 11.40%)
CWE
CWE-787
Published
2024-01-25T15:54:23.102Z
Last modified
2025-11-20T07:24:31.172Z
CVSS vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

01What is this vulnerability?

A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise. This flaw is only exploitable during the early boot phase, an attacker needs to…

02Affected products

VendorProductVersions
Red HatRed Hat Enterprise Linux 70:15.8-3.el7
Red HatRed Hat Enterprise Linux 70:15.8-1.el7
Red HatRed Hat Enterprise Linux 80:15.8-4.el8_9
Red HatRed Hat Enterprise Linux 8.2 Advanced Update Support0:15.8-2.el8_2
Red HatRed Hat Enterprise Linux 8.2 Telecommunications Update Service0:15.8-2.el8_2
Red HatRed Hat Enterprise Linux 8.2 Update Services for SAP Solutions0:15.8-2.el8_2
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support0:15.8-2.el8_4
Red HatRed Hat Enterprise Linux 8.4 Telecommunications Update Service0:15.8-2.el8_4
Red HatRed Hat Enterprise Linux 8.4 Update Services for SAP Solutions0:15.8-2.el8_4
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support0:15.8-2.el8_6
Red HatRed Hat Enterprise Linux 8.8 Extended Update Support0:15.8-2.el8
Red HatRed Hat Enterprise Linux 8.8 Extended Update Support0:15.8-2.el8
Red HatRed Hat Enterprise Linux 90:15.8-4.el9_3
Red HatRed Hat Enterprise Linux 9.0 Extended Update Support0:15.8-3.el9
Red HatRed Hat Enterprise Linux 9.0 Extended Update Support0:15.8-2.el9
Red HatRed Hat Enterprise Linux 9.0 Extended Update Support0:15.8-2.el9
Red HatRed Hat Enterprise Linux 9.2 Extended Update Support0:15.8-3.el9_2

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

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07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

09References

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