DoS via Block Size Mismatch in nbdkit Server
CVE-2025-47711 Published on June 9, 2025
Nbdkit: nbdkit-server: off-by-one error when processing block status may lead to a denial of service
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.
Vulnerability Analysis
CVE-2025-47711 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public.
Weakness Type
What is an off-by-five Vulnerability?
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
CVE-2025-47711 has been classified to as an off-by-five vulnerability or weakness.
Products Associated with CVE-2025-47711
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Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.