CVE-2023-5215: Red Hat Enterprise Linux

Medium severity, CVSS 6.5. EPSS: 0.8% chance of exploitation in the next 30 days.

A flaw was found in libnbd. A server can reply with a block size larger than 2^63 (the NBD spec states the size is a 64-bit unsigned value). This issue could lead to an application crash or other unintended behavior for NBD clients that doesn't treat the return value of the nbd_get_size() function correctly.

Affected products

• Red Hat Enterprise Linux: version 8.0 only; version 9.0 only
• Red Hat Libnbd: before 1.18.0 (fixed in 1.18.0)

Published 2023-09-28. Last modified 2026-06-17.