Apache log4net: NUL character truncates EventLogAppender records
Improper Neutralization of Null Byte or NUL Character vulnerability in the EventLogAppender of Apache log4net. A NUL character in logged content ended the Windows Event Log record at that point, so everything the layout rendered after it, including exception text and trailing fields, was silently not stored. A party whose data reaches a log message could hide the rest of that record. Only applications on Windows that use EventLogAppender are affected. This issue affects Apache log4net: from 1.2.9 before 3.5.0. Users are recommended to upgrade to version 3.5.0, which fixes the issue.
CVE-2026-105239
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-105239
Apache log4net
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Apache log4net
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "Apache Software Foundation",
"product": "Apache log4net",
"versions": [
{
"status": "affected",
"version": "1.2.9",
"lessThan": "3.5.0",
"versionType": "semver"
}
],
"packageURL": "pkg:nuget/log4net",
"packageName": "log4net",
"collectionURL": "https://nuget.org/packages",
"defaultStatus": "unaffected"
},
{
"repo": "https://gitbox.apache.org/repos/asf/logging-log4net.git",
"vendor": "Apache Software Foundation",
"product": "Apache log4net",
"versions": [
{
"status": "affected",
"version": "02e1e115435888485f2e28b414d267e39e799e07",
"lessThan": "dc5855a0720c91590fd7a81d729ea01fdd69e000",
"versionType": "git"
}
],
"packageURL": "pkg:nuget/log4net",
"packageName": "log4net",
"collectionURL": "https://nuget.org/packages",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-105239
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #11750 · Revision 1
- Added to Heist Feed
- Publisher date