CVE Feed

    Dashboard / CVE / CVE-2026-34478

    CVE-2026-34478

    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.

    Published:Apr 10, 2026
    Last Modified:Apr 24, 2026
    EPS:Apr 10, 2026
    EPSS Score:0.00191
    CVSS Score:7.5

    Affected Products

    Vendor
    Apache
    Product
    Log4j

    Exploits

    No exploit reference

    Related CVEs

    CVE-2026-34481 (CVSS 6.3) — Apache Log4j's JsonTemplateLayout https://logging.apache.org/log4j/2.x/manual/json-template-layout.html , in …
    CVE-2026-34480 (CVSS 6.9) — Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in version…
    CVE-2026-34479 (CVSS 6.9) — The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML …
    CVE-2026-34477 (CVSS 6.3) — The fix for CVE-2025-68161 https://logging.apache.org/security.html#CVE-2025-68161 was incomplete: it addres…
    CVE-2025-68161 (CVSS 6.3) — The Socket Appender in Apache Log4j Core versions 2.0-beta9 through 2.25.2 does not perform TLS hostname verif…
    CVE-2023-26464 (CVSS 7.5) — ** UNSUPPORTED WHEN ASSIGNED ** When using the Chainsaw or SocketAppender components with Log4j 1.x on JRE le…
    CVE-2022-23305 (CVSS 9.8) — By design, the JDBCAppender in Log4j 1.2.x accepts an SQL statement as a configuration parameter where the val…
    CVE-2022-23302 (CVSS 8.8) — JMSSink in all versions of Log4j 1.x is vulnerable to deserialization of untrusted data when the attacker has …
    CVE-2022-23307 (CVSS 8.8) — CVE-2020-9493 identified a deserialization issue that was present in Apache Chainsaw. Prior to Chainsaw V2.0 C…
    CVE-2021-44832 (CVSS 6.6) — Apache Log4j2 versions 2.0-beta7 through 2.17.0 (excluding security fix releases 2.3.2 and 2.12.4) are vulnera…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High