CVE-2026-105243

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Source
https://cve.org/CVERecord?id=CVE-2026-105243
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-105243.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-105243
Downstream
Published
2026-10-06T19:51:25Z
Modified
2026-10-08T02:51:15Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
Summary
Apache log4net: Oversize EventLogAppender record silently discarded
Details

Insufficient Logging vulnerability in the EventLogAppender of Apache log4net.

Long messages were truncated to a fixed size that exceeds what the Windows Event Log accepts once the log and source names are counted, and the event log then stored nothing and reported nothing. A party whose data reaches a log message could suppress the whole record by making it long enough. 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.

Database specific 
{
    "cna_assigner": "apache",
    "cwe_ids": [
        "CWE-778"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105243.json"
}
References

Affected packages

Git / gitbox.apache.org/repos/asf/logging-log4net.git

Affected ranges

Type
GIT
Repo
https://gitbox.apache.org/repos/asf/logging-log4net.git
Events
Introduced
02e1e115435888485f2e28b414d267e39e799e07
Fixed
28fbfb25678c48a8cc5bc9b94ead0dddfc39ffed
Type
GIT
Repo
https://github.com/apache/logging-log4net
Events
Introduced
18a96716af733f7c6e4956526acdcc117a1bd461
Fixed
f7794ae187ab2e228e1754cb478568dd305d1b32
Fixed
28fbfb25678c48a8cc5bc9b94ead0dddfc39ffed
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "1.2.9"
        },
        {
            "fixed": "3.5.0"
        }
    ],
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

rc/3.*
rc/3.0.1-preview.1
rc/3.0.1-preview.2
rc/3.0.1-rc1
rc/3.0.2-rc1
rc/3.0.3-preview.1
rc/3.0.3-rc1
rc/3.0.4-preview.1
rc/3.0.4-rc1
rc/3.1.0-rc1
rc/3.2.0-preview.1
rc/3.2.0-rc1
rc/3.3.0-rc1
rc/3.3.1-rc1
rc/3.3.2-rc1
rc/3.4.0-preview.1
rc/3.4.0-rc1
rc/3.4.1-preview.1
Other
rc/temp
rel/2.*
rel/2.0.10
rel/2.0.11
rel/2.0.12
rel/2.0.13
rel/2.0.14
rel/2.0.15
rel/2.0.16
rel/2.0.17
rel/2.x
rel/3.*
rel/3.0.1
rel/3.0.2
rel/3.0.3
rel/3.0.4
rel/3.1.0
rel/3.2.0
rel/3.3.0
rel/3.3.1
rel/3.3.2
rel/3.4.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-105243.json"