Vulnerability-Lookup

BDU:2026-05260 (CVE-2026-34478)

Vulnerability from fstec – Published: 2026-04-14 – Updated: 2026-07-23 – View on bdu.fstec.ru Fixed

Title

Уязвимость компонента Rfc5424Layout библиотеки журналирования Apache Log4j Core, позволяющая нарушителю оказать влияние на целостность защищаемой информации

Summary

Уязвимость компонента Rfc5424Layout библиотеки журналирования Apache Log4j Core связана с неправильной обработкой выходных данных для журналов регистрации. Эксплуатация уязвимости может позволить нарушителю, действующему удаленно, оказать влияние на целостность защищаемой информации

Severity

5.0 (Medium) CVSS 2.0


                      
                        AV:N/AC:L/Au:N/C:N/I:P/A:N

5.3 (Medium) CVSS 3.1


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

6.9 (Medium) CVSS 4.0


                      
                        CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

Class

Code vulnerability

Status

Confirmed by the vendor

Exploitation

Resource manipulation, Functionality abuse

Incidents

Being clarified

Remediation

Software update

CWE

CWE-117 - Неправильная обработка выходных данных для журналов регистрации
CWE-684 - Некорректное представление заданных функций

Aliases

CVE-2026-34478

References

4 references

URL
https://www.openwall.com/lists/oss-security/2026/04/10/7
https://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt
https://github.com/apache/logging-log4j2/pull/4074
https://logging.apache.org/security.html#CVE-2026-34478

Impacted products

2 products from 2 vendors

Vendors

Apache Software Foundation, АО «СберТех»

Products

Apache Log4j Core, Platform V IAM SE

Versions

от 2.21.0 до 2.25.3 включительно (Apache Log4j Core), до 2.3.1 (Platform V IAM SE)

Product types

Application software

Mitigations

Использование рекомендаций: https://github.com/apache/logging-log4j2/pull/4074 https://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt Для Platform V IAM SE: Обновление до версии Platform V IAM SE 2.3.1

JSON

To clipboard

{
  "CVSS 2.0": "AV:N/AC:L/Au:N/C:N/I:P/A:N",
  "CVSS 3.0": "AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
  "CVSS 4.0": "AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N",
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "Apache Software Foundation, \u0410\u041e \u00ab\u0421\u0431\u0435\u0440\u0422\u0435\u0445\u00bb",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "\u043e\u0442 2.21.0 \u0434\u043e 2.25.3 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Apache Log4j Core), \u0434\u043e 2.3.1 (Platform V IAM SE)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439:\nhttps://github.com/apache/logging-log4j2/pull/4074\nhttps://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt\n\n\u0414\u043b\u044f Platform V IAM SE:\n\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u0434\u043e \u0432\u0435\u0440\u0441\u0438\u0438 Platform V IAM SE 2.3.1",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "25.12.2025",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "23.07.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "14.04.2026",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2026-05260",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2026-34478",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Apache Log4j Core, Platform V IAM SE",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": null,
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u043c\u043f\u043e\u043d\u0435\u043d\u0442\u0430 Rfc5424Layout \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 \u0436\u0443\u0440\u043d\u0430\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f Apache Log4j Core, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u043e\u043a\u0430\u0437\u0430\u0442\u044c \u0432\u043b\u0438\u044f\u043d\u0438\u0435 \u043d\u0430 \u0446\u0435\u043b\u043e\u0441\u0442\u043d\u043e\u0441\u0442\u044c \u0437\u0430\u0449\u0438\u0449\u0430\u0435\u043c\u043e\u0439 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u041d\u0435\u043f\u0440\u0430\u0432\u0438\u043b\u044c\u043d\u0430\u044f \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0430 \u0432\u044b\u0445\u043e\u0434\u043d\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445 \u0434\u043b\u044f \u0436\u0443\u0440\u043d\u0430\u043b\u043e\u0432 \u0440\u0435\u0433\u0438\u0441\u0442\u0440\u0430\u0446\u0438\u0438 (CWE-117), \u041d\u0435\u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u043e\u0435 \u043f\u0440\u0435\u0434\u0441\u0442\u0430\u0432\u043b\u0435\u043d\u0438\u0435 \u0437\u0430\u0434\u0430\u043d\u043d\u044b\u0445 \u0444\u0443\u043d\u043a\u0446\u0438\u0439 (CWE-684)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u043c\u043f\u043e\u043d\u0435\u043d\u0442\u0430 Rfc5424Layout \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 \u0436\u0443\u0440\u043d\u0430\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f Apache Log4j Core \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u043d\u0435\u043f\u0440\u0430\u0432\u0438\u043b\u044c\u043d\u043e\u0439 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u043e\u0439 \u0432\u044b\u0445\u043e\u0434\u043d\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445 \u0434\u043b\u044f \u0436\u0443\u0440\u043d\u0430\u043b\u043e\u0432 \u0440\u0435\u0433\u0438\u0441\u0442\u0440\u0430\u0446\u0438\u0438. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e, \u0434\u0435\u0439\u0441\u0442\u0432\u0443\u044e\u0449\u0435\u043c\u0443 \u0443\u0434\u0430\u043b\u0435\u043d\u043d\u043e, \u043e\u043a\u0430\u0437\u0430\u0442\u044c \u0432\u043b\u0438\u044f\u043d\u0438\u0435 \u043d\u0430 \u0446\u0435\u043b\u043e\u0441\u0442\u043d\u043e\u0441\u0442\u044c \u0437\u0430\u0449\u0438\u0449\u0430\u0435\u043c\u043e\u0439 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u0438",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": null,
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u0441\u0443\u0440\u0441\u0430\u043c\u0438, \u0417\u043b\u043e\u0443\u043f\u043e\u0442\u0440\u0435\u0431\u043b\u0435\u043d\u0438\u0435 \u0444\u0443\u043d\u043a\u0446\u0438\u043e\u043d\u0430\u043b\u043e\u043c",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://www.openwall.com/lists/oss-security/2026/04/10/7\nhttps://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt\nhttps://github.com/apache/logging-log4j2/pull/4074\nhttps://logging.apache.org/security.html#CVE-2026-34478",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041f\u0440\u0438\u043a\u043b\u0430\u0434\u043d\u043e\u0435 \u041f\u041e \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-117, CWE-684",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 5)\n\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.1 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 5,3)\n\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u043e\u0446\u0435\u043d\u043a\u0430 CVSS 4.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 6,9)"
}

CVE-2026-34478 (GCVE-0-2026-34478)

Vulnerability from cvelistv5 – Published: 2026-04-10 15:40 – Updated: 2026-04-10 17:50

Title

Apache Log4j Core: Log injection in Rfc5424Layout due to silent configuration incompatibility

Summary

Apache Log4j Core's Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout , in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes. Two distinct issues affect users of stream-based syslog services who configure Rfc5424Layout directly: * The newLineEscape attribute was silently renamed, causing newline escaping to stop working for users of TCP framing (RFC 6587), exposing them to CRLF injection in log output. * The useTlsMessageFormat attribute was silently renamed, causing users of TLS framing (RFC 5425) to be silently downgraded to unframed TCP (RFC 6587), without newline escaping. Users of the SyslogAppender are not affected, as its configuration attributes were not modified. Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.

Severity

6.9 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-10 17:48 UTC

CWE

CWE-684 - Incorrect Provision of Specified Functionality
CWE-117 - Improper Output Neutralization for Logs

Assigner

apache mitre root

References

6 references

URL	Tags
https://github.com/apache/logging-log4j2/pull/4074	patch
https://logging.apache.org/security.html#CVE-2026-34478	vendor-advisory
https://logging.apache.org/cyclonedx/vdr.xml	vendor-advisory
https://logging.apache.org/log4j/2.x/manual/layou…	related
https://lists.apache.org/thread/3k1clr2l6vkdnl4cb…	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/04/10/7

Impacted products

1 product

Vendor	Product	Version
Apache Software Foundation	Apache Log4j Core	Affected: 2.21.0 , < 2.25.4 (maven) Affected: 3.0.0-beta1 , ≤ 3.0.0-beta3 (maven) cpe:2.3:a:apache:log4j::::::::

Credits

Samuli Leinonen

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2026-04-10T16:18:17.528Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/04/10/7"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-34478",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-10T17:48:27.852992Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-10T17:50:12.484Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.maven.apache.org/maven2",
          "cpes": [
            "cpe:2.3:a:apache:log4j:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "packageName": "org.apache.logging.log4j:log4j-core",
          "packageURL": "pkg:maven/org.apache.logging.log4j/log4j-core",
          "product": "Apache Log4j Core",
          "vendor": "Apache Software Foundation",
          "versions": [
            {
              "lessThan": "2.25.4",
              "status": "affected",
              "version": "2.21.0",
              "versionType": "maven"
            },
            {
              "lessThanOrEqual": "3.0.0-beta3",
              "status": "affected",
              "version": "3.0.0-beta1",
              "versionType": "maven"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Samuli Leinonen"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eApache Log4j Core\u0027s \u003ccode\u003e\u003ca target=\"_blank\" rel=\"nofollow\" href=\"https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout\"\u003eRfc5424Layout\u003c/a\u003e\u003c/code\u003e, in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes.\u003c/p\u003e\u003cp\u003eTwo distinct issues affect users of stream-based syslog services who configure \u003ccode\u003eRfc5424Layout\u003c/code\u003e directly:\u003c/p\u003e\u003cul\u003e\u003cli\u003eThe \u003ccode\u003enewLineEscape\u003c/code\u003e attribute was silently renamed, causing newline escaping to stop working for users of TCP framing (RFC 6587), exposing them to CRLF injection in log output.\u003c/li\u003e\u003cli\u003eThe \u003ccode\u003euseTlsMessageFormat\u003c/code\u003e attribute was silently renamed, causing users of TLS framing (RFC 5425) to be silently downgraded to unframed TCP (RFC 6587), without newline escaping.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003eUsers of the \u003ccode\u003eSyslogAppender\u003c/code\u003e are not affected, as its configuration attributes were not modified.\u003c/p\u003e\u003cp\u003eUsers are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.\u003c/p\u003e"
            }
          ],
          "value": "Apache Log4j Core\u0027s  Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout , in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes.\n\nTwo distinct issues affect users of stream-based syslog services who configure Rfc5424Layout directly:\n\n  *  The newLineEscape attribute was silently renamed, causing newline escaping to stop working for users of TCP framing (RFC 6587), exposing them to CRLF injection in log output.\n  *  The useTlsMessageFormat attribute was silently renamed, causing users of TLS framing (RFC 5425) to be silently downgraded to unframed TCP (RFC 6587), without newline escaping.\n\n\nUsers of the SyslogAppender are not affected, as its configuration attributes were not modified.\n\nUsers are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "other": {
            "content": {
              "text": "moderate"
            },
            "type": "Textual description of severity"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-684",
              "description": "CWE-684 Incorrect Provision of Specified Functionality",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-117",
              "description": "CWE-117 Improper Output Neutralization for Logs",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-10T15:40:17.713Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "shortName": "apache"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/apache/logging-log4j2/pull/4074"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://logging.apache.org/security.html#CVE-2026-34478"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://logging.apache.org/cyclonedx/vdr.xml"
        },
        {
          "tags": [
            "related"
          ],
          "url": "https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2025-12-25T12:58:00.000Z",
          "value": "Vulnerability reported by Samuli Leinonen"
        },
        {
          "lang": "en",
          "time": "2026-03-10T16:00:00.000Z",
          "value": "Candidate patch shared internally by Piotr P. Karwasz"
        },
        {
          "lang": "en",
          "time": "2026-03-24T18:41:00.000Z",
          "value": "Fix shared publicly by Piotr P. Karwasz as pull request #4074"
        },
        {
          "lang": "en",
          "time": "2026-03-25T11:02:00.000Z",
          "value": "Fix verified by reporter"
        },
        {
          "lang": "en",
          "time": "2026-03-28T11:19:00.000Z",
          "value": "Log4j 2.25.4 released"
        }
      ],
      "title": "Apache Log4j Core: Log injection in Rfc5424Layout due to silent configuration incompatibility",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
    "assignerShortName": "apache",
    "cveId": "CVE-2026-34478",
    "datePublished": "2026-04-10T15:40:17.713Z",
    "dateReserved": "2026-03-28T13:17:35.586Z",
    "dateUpdated": "2026-04-10T17:50:12.484Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

BDU:2026-05260 (CVE-2026-34478)

CVE-2026-34478 (GCVE-0-2026-34478)

Tags

Sightings

Nomenclature

Related by attack behaviour