GHSA-R5VQ-477M-WCFC
Vulnerability from github – Published: 2026-10-06 21:31 – Updated: 2026-10-06 21:31Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net.
Content that the mail file writer cannot encode, such as an unpaired UTF-16 surrogate, made the write throw. Every buffered event in the batch was discarded, not only the one carrying the content, and a truncated mail could be left in the pickup directory. A party whose data reaches a log message could suppress the records of other events. Only applications that use SmtpPickupDirAppender 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.
{
"affected": [],
"aliases": [
"CVE-2026-105241"
],
"database_specific": {
"cwe_ids": [
"CWE-176"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-06T20:17:15Z",
"severity": "MODERATE"
},
"details": "Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net.\n\nContent that the mail file writer cannot encode, such as an unpaired UTF-16 surrogate, made the write throw. Every buffered event in the batch was discarded, not only the one carrying the content, and a truncated mail could be left in the pickup directory. A party whose data reaches a log message could suppress the records of other events. Only applications that use SmtpPickupDirAppender are affected.\n\nThis issue affects Apache log4net: from 1.2.9 before 3.5.0.\n\nUsers are recommended to upgrade to version 3.5.0, which fixes the issue.",
"id": "GHSA-r5vq-477m-wcfc",
"modified": "2026-10-06T21:31:59Z",
"published": "2026-10-06T21:31:59Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105241"
},
{
"type": "WEB",
"url": "https://github.com/apache/logging-log4net/pull/315"
},
{
"type": "WEB",
"url": "https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
}
]
}
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