CVE-2026-101017
Description
A flaw was found in OpenDMARC. A NULL pointer dereference occurs in the strcasecmp call within libopendmarc/opendmarc_policy.c during subdomain walking when processing Domain-based Message Authentication, Reporting, and Conformance (DMARC) records. A remote attacker could exploit this flaw by sending a specially crafted email that triggers the subdomain walking code path, potentially causing the OpenDMARC milter process to crash, resulting in a denial of service (DoS).
Statement
OpenDMARC is not shipped in any Red Hat product. It is available only in Fedora and EPEL community repositories.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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