CVE-2026-43405

A flaw was found in the libceph component of the Linux kernel. This vulnerability occurs in the ceph_monmap_decode() function due to incorrect handling of non-negative values, where int variables are used instead of u32 for blob_len and num_mon. An attacker could exploit this by sending a specially crafted message with an excessively large num_mon value. This could lead to an attempt to allocate a very large amount of memory, resulting in a Denial of Service (DoS) condition.

Red Hat acknowledges the upstream Linux kernel correction for «libceph» as described in COMMENT_ZERO. Fixes are delivered through standard kernel errata for supported products. Operational exposure depends on whether this subsystem or driver is active in your configuration.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the ceph module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.