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GHSA-R886-MF8R-26C7

Vulnerability from github – Published: 2026-10-06 21:31 – Updated: 2026-10-06 21:31

Details

Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.

Reading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the layout throw and the appender discarded the whole event. A sender could suppress the log record of their own request. Only applications on ASP.NET for .NET Framework whose layout uses %aspnet-request are affected.

This issue affects Apache log4net: from 1.2.11 before 3.5.0.

Users are recommended to upgrade to version 3.5.0, which fixes the issue.

Severity

5.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-105242"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-755"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-06T20:17:16Z",
    "severity": "MODERATE"
  },
  "details": "Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.\n\nReading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the layout throw and the appender discarded the whole event. A sender could suppress the log record of their own request. Only applications on ASP.NET for .NET Framework whose layout uses %aspnet-request are affected.\n\nThis issue affects Apache log4net: from 1.2.11 before 3.5.0.\n\nUsers are recommended to upgrade to version 3.5.0, which fixes the issue.",
  "id": "GHSA-r886-mf8r-26c7",
  "modified": "2026-10-06T21:31:59Z",
  "published": "2026-10-06T21:31:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105242"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apache/logging-log4net/pull/316"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apache/logging-log4net/commit/145203420c579a703008b4b723b6a080757f4964"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread.html/zg6dbqm4ztm7j3c21nfsqj0yxm5yrpdx"
    }
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  "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"
    }
  ]
}

CVE-2026-105242 (GCVE-0-2026-105242)

Vulnerability from cvelistv5 – Published: 2026-10-06 19:50 – Updated: 2026-10-07 06:11

Title

Apache log4net: Request validation failure drops the event in the aspnet-request converter

Summary

Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net. Reading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the layout throw and the appender discarded the whole event. A sender could suppress the log record of their own request. Only applications on ASP.NET for .NET Framework whose layout uses %aspnet-request are affected. This issue affects Apache log4net: from 1.2.11 before 3.5.0. Users are recommended to upgrade to version 3.5.0, which fixes the issue.

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CWE

CWE-755 - Improper Handling of Exceptional Conditions

Assigner

apache mitre root Scorecard

References

4 references

URL	Tags
https://github.com/apache/logging-log4net/pull/316	patch
https://github.com/apache/logging-log4net/commit/…	patch
https://lists.apache.org/thread.html/zg6dbqm4ztm7…	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/1…

Impacted products

2 products

Vendor	Product	Version
Apache Software Foundation	Apache log4net	Affected: 1.2.11 , < 3.5.0 (semver)
Apache Software Foundation	Apache log4net	Affected: 243f1e9f3ee235955bade4b4fe664a903378719a , < 145203420c579a703008b4b723b6a080757f4964 (git)

Credits

The Apache Software Foundation Claude Security Jan Friedrich

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-R886-MF8R-26C7

CVE-2026-105242 (GCVE-0-2026-105242)

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