Bug#1133846: apache-log4j2: CVE-2026-34481

[Salvatore Bonaccorso]

Source: apache-log4j2
Version: 2.19.0-2
Severity: important
Tags: security upstream
X-Debbugs-Cc: carnil at debian.org, Debian Security Team <team at security.debian.org>

Hi,

The following vulnerability was published for apache-log4j2.

CVE-2026-34481[0]:
| Apache Log4j's  JsonTemplateLayout
| https://logging.apache.org/log4j/2.x/manual/json-template-
| layout.html , in versions up to and including 2.25.3, produces
| invalid JSON output when log events contain non-finite floating-
| point values (NaN, Infinity, or -Infinity), which are prohibited by
| RFC 8259. This may cause downstream log processing systems to reject
| or fail to index affected records.  An attacker can exploit this
| issue only if both of the following conditions are met:    *  The
| application uses JsonTemplateLayout.   *  The application logs a
| MapMessage containing an attacker-controlled floating-point value.
| Users are advised to upgrade to Apache Log4j JSON Template Layout
| 2.25.4, which corrects this issue.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-34481
    https://www.cve.org/CVERecord?id=CVE-2026-34481
[1] https://lists.apache.org/thread/n34zdv00gbkdbzt2rx9rf5mqz6lhopcv
[2] https://logging.apache.org/security.html#CVE-2026-34481
[3] https://github.com/apache/logging-log4j2/pull/4080
[4] https://github.com/apache/logging-log4j2/commit/2c4dd1db372c59ad73aca88e281635fe30072268

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore