CVE-2026-100888

Name of the Vulnerable Software and Affected Versions OpenDKIM versions prior to 2.11.1

Description A weakness exists in the DKIM Signature Header Selection component within the dkim canon selecthdrs() function of the libopendkim/dkim-canon.c file. A remote attacker can manipulate the h argument to trigger an out-of-bounds write, which occurs when data is written outside the intended memory boundary of a buffer.

Recommendations Update OpenDKIM to a version newer than 2.11.0. As a temporary mitigation, restrict access to the dkim canon selecthdrs() function to minimize the risk of exploitation.