CVE-2025-47711 Nbdkit: nbdkit-server: off-by-one error when processing block status may lead to a denial of service
An off-by-one error in nbdkit server allows remote attackers to cause a denial of service via crafted block status responses.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-47711?
CVE-2025-47711 is a medium-severity denial of service vulnerability in Redhat Enterprise Linux, published on 9 Jun 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
There's a flaw in the nbdkit server when handling responses from its plugins regarding the status of data blocks. If a client makes a specific request for a very large data range, and a plugin responds with an even larger single block, the nbdkit server can encounter a critical internal error, leading to a denial-of-service.
Weakness: CWE-193
Which versions are affected by CVE-2025-47711?
It affects 3 products.
Products include Nbdkit Project Nbdkit, Redhat Enterprise Linux, Redhat Enterprise Linux Advanced Virtualization.
How do I fix CVE-2025-47711?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-47711 being exploited?
There is no known exploitation of CVE-2025-47711 in the wild and no public exploit code.
Other vulnerabilities in Redhat Enterprise Linux
Sources
Also known as AZL-63801, AZL-63878, CLSA-2026-1775809438, DEBIAN-CVE-2025-47711, GHSA-c8xj-fr2w-pjfc, UBUNTU-CVE-2025-47711.