Apache log4net: RemoteSyslogAppender silently deletes non-ASCII content
Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net. Every character outside visible ASCII and space was removed from the record instead of being escaped, so non-ASCII text and control characters such as tabs disappeared without notice. A party whose data reaches a log message could make a distinct value look identical in the record, for example a user name holding a zero-width space logged as admin. Only applications that use RemoteSyslogAppender are affected. This issue affects Apache log4net: from 1.2.12 before 3.5.0. Users are recommended to upgrade to version 3.5.0, which fixes the issue.
CVE-2026-105244
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-2026-105244
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": "1.2.12",
"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": "56a2e146e21ff4737e1ff3ec308810e667873947",
"lessThan": "77717061b20d4346b6c0ce6b54643d85fb348bc7",
"versionType": "git"
}
],
"packageURL": "pkg:nuget/log4net",
"packageName": "log4net",
"collectionURL": "https://nuget.org/packages",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-105244
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #11892 · Revision 1
- Added to Heist Feed
- Publisher date