Vulnerability in Shim (CVE-2023-40548)
Summary
Vulnerability in Shim (CVE-2023-40548). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2023-40548 has been found in Shim.
Successful exploitation can lead to full system takeover. CVSS score: 7.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Shim CVE-2023-40548" on the vendor's site.
CVE-2023-40548 (Shim) — CWE-190 / CVSS v3 7.4
Attack vector: local / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-190) exists in Shim.
Check the vendor advisory for the affected versions of Shim.
Severity: High (CVSS 7.4/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Shim' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Shim' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Shimを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2023-40548 shim Fixed in: 15.8-1~deb11u1
References
- patch access.redhat.com
- patch bugzilla.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web lists.debian.org