# CVE-2025-47711: Nbdkit: nbdkit-server: off-by-one error when processing block status may lead to a denial of service

CVE-2025-47711 is fixed in nbdkit on 1 platform, first by DEBIAN-CVE-2025-47711, released June 9, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-47711
- Priority: Routine
- CVSS: 6.5 (Moderate)
- EPSS: 0.0048
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 9, 2025
- Weakness: Off-by-one Error
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-47711

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nbdkit Debian 13.5 (trixie) | 1.42.3-1 | [DEBIAN-CVE-2025-47711](https://patchblox.com/security/data/fix/linux/debian-cve-2025-47711.md) | Jun 9, 2025 |
| Linux | nbdkit Debian 14 | 1.42.3-1 | [DEBIAN-CVE-2025-47711](https://patchblox.com/security/data/fix/linux/debian-cve-2025-47711.md) | Jun 9, 2025 |
| Linux | nbdkit opensuse-leap 15.6 | 1.36.5-150400.3.9.1 | [SUSE-SU-2025:01889-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01889-1.md) | Jun 11, 2025 |
| Linux | nbdkit sles 15.6 | 1.36.5-150400.3.9.1 | [SUSE-SU-2025:01889-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01889-1.md) | Jun 11, 2025 |
| Linux | nbdkit sles 15.7 | 1.40.6-150700.4.3.1 | [SUSE-SU-2025:01888-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01888-1.md) | Jun 11, 2025 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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