Apache log4net: NUL character truncates OutputDebugStringAppender records
Improper Neutralization of Null Byte or NUL Character vulnerability in the OutputDebugStringAppender of Apache log4net. A NUL character in logged content ended the debug output record at that point, so everything the layout rendered after it, including exception text and trailing fields, was silently lost. A party whose data reaches a log message could hide the rest of that record. Only applications on Windows that use OutputDebugStringAppender 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-2026-105240
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-2026-105240
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": "6046fe9d7f353b49fe995361c071ec2eea8f7ef6",
"versionType": "git"
}
],
"packageURL": "pkg:nuget/log4net",
"packageName": "log4net",
"collectionURL": "https://nuget.org/packages",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-105240
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #11967 · Revision 1
- Added to Heist Feed
- Publisher date