6.3

CVE-2026-34477

Apache Log4j Core: verifyHostName attribute silently ignored in TLS configuration, allowing hostname verification bypass

The fix for  CVE-2025-68161 https://logging.apache.org/security.html#CVE-2025-68161  was incomplete: it addressed hostname verification only when enabled via the  log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName  system property, but not when configured through the  verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName  attribute of the <Ssl> element.

Although the verifyHostName configuration attribute was introduced in Log4j Core 2.12.0, it was silently ignored in all versions through 2.25.3, leaving TLS connections vulnerable to interception regardless of the configured value.

A network-based attacker may be able to perform a man-in-the-middle attack when all of the following conditions are met:

  *  An SMTP, Socket, or Syslog appender is in use.
  *  TLS is configured via a nested <Ssl> element.
  *  The attacker can present a certificate issued by a CA trusted by the appender's configured trust store, or by the default Java trust store if none is configured.
This issue does not affect users of the HTTP appender, which uses a separate  verifyHostname https://logging.apache.org/log4j/2.x/manual/appenders/network.html#HttpAppender-attr-verifyHostName  attribute that was not subject to this bug and verifies host names by default.

Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Apache ≫ Log4j Version >= 2.12.0 < 2.25.4
Apache ≫ Log4j Version3.0.0 Updatealpha1
Apache ≫ Log4j Version3.0.0 Updatealpha1_rc1
Apache ≫ Log4j Version3.0.0 Updatealpha1_rc2
Apache ≫ Log4j Version3.0.0 Updatebeta1
Apache ≫ Log4j Version3.0.0 Updatebeta2
Apache ≫ Log4j Version3.0.0 Updatebeta3
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.12% 0.303
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.9 2.2 3.6
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
security@apache.org 6.3 0 0
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE-295 Improper Certificate Validation

The product does not validate, or incorrectly validates, a certificate.

CWE-297 Improper Validation of Certificate with Host Mismatch

The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host.