CVE-2025-47712: Nbd: nbdkit: integer overflow triggers an assertion resulting in denial of service
A flaw exists in the nbdkit "blocksize" filter that can be triggered by a specific type of client request. When a client requests block status information for a very large data range, exceeding a certain limit, it causes an internal error in the nbdkit, leading to a denial of service.
Other sources
Nbd: nbdkit: integer overflow triggers an assertion resulting in denial of service
— Microsoft
The nbdkit blocksize filter had a bug where any client block status request larger than (232 - the minimum blocksize) would round up to 4G using a 32-bit variable. This wrapped around to zero, triggering an assertion failure.
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 1.35.3-4 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 1.35.3-7
Event History
Frequently Asked Questions
What is the severity of CVE-2025-47712?
The severity of CVE-2025-47712 is classified as a denial of service vulnerability.
How do I fix CVE-2025-47712?
Fixing CVE-2025-47712 involves applying the latest security patches released by the vendor of the nbdkit software.
What systems are affected by CVE-2025-47712?
CVE-2025-47712 affects systems using the nbdkit with the 'blocksize' filter.
What does CVE-2025-47712 allow an attacker to do?
CVE-2025-47712 allows an attacker to trigger a denial of service condition by requesting block status information for excessive data ranges.
Is there a workaround for CVE-2025-47712?
Currently, there are no recommended workarounds for CVE-2025-47712 other than avoiding the use of the vulnerable functionality.