CVE-2023-40546: fedoraproject fedora NULL Pointer Dereference
Vulnerability summary
CVE-2023-40546 is a medium (CVSS 6.2) NULL Pointer Dereference vulnerability in fedoraproject fedora. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 36.7% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 14 · Related 4Timeline
- 29-01-2024PublishedVulnerability first disclosed.
- 20-11-2025Last modifiedVulnerability information updated.
Description
A flaw was found in Shim when an error happened while creating a new ESL variable. If Shim fails to create the new variable, it tries to print an error message to the user; however, the number of parameters used by the logging function doesn't match the format string used by it, leading to a crash under certain circumstances.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
EPSS trend
Probability
0.44%
Chance of exploitation in the next 30 days
Percentile
37%
Versus all other CVEs
30-day change
0.00 pp
From 0.44% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Redhat2 products
- enterprise_linux8.0 | 9.0
- shim< 15.8
Ubuntu2 products
- shimAll versions (No fix recorded) | < 15.8-0ubuntu1
- shim-signedAll versions (No fix recorded) | < 1.40.10 | < 1.51.4 | < 1.58
Debian1 product
- shim< 15.8-1~deb12u1 | < 15.8-1
Fedoraproject1 product
- fedoraEOL39
4 vendors · 6 products
