CVE-2025-47712: Nbd: nbdkit: integer overflow triggers an assertion resulting in denial of service

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-09 · updated 2026-06-30
Weakness: CWE-190

Description

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.

Affected products

nbdkit: all versions

References

https://access.redhat.com/security/cve/CVE-2025-47712
https://bugzilla.redhat.com/show_bug.cgi?id=2365724
https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/67E7AASHHADIY7VAD3FFW2I67LTWVWYF/

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