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

Status: published. Published: 2025-06-09. Updated: 2026-11-05.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

-  /  (nbdkit): ≥ 1.21.16; < 1.38.6 (affected, semver); ≥ 1.40.0; < 1.40.6 (affected, semver); ≥ 1.42.0; < 1.42.3 (affected, semver). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (nbdkit): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (nbdkit): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (virt:rhel/nbdkit): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 Advanced Virtualization (virt:8.2/nbdkit): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 Advanced Virtualization (virt:av/nbdkit): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (nbdkit): Version range not reported. Source: CNA: redhat

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:nbdkit_project:nbdkit:-:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      },
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
            "vulnerable": false
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
            "vulnerable": false
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*",
            "vulnerable": false
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*",
            "vulnerable": false
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux_advanced_virtualization:8.0:*:*:*:*:*:*:*",
            "vulnerable": false
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "AND"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: NVD: secalert@redhat.com

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: NVD: nvd@nist.gov

- CISA KEV: No listing in collected sources

- EPSS: 0.53% as of 2026-11-05; percentile 44.78%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-190

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2025-47712 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2365724 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/67E7AASHHADIY7VAD3FFW2I67LTWVWYF/ (CNA: redhat)

- https://access.redhat.com/security/cve/CVE-2025-47712 (secalert@redhat.com; Third Party Advisory)

- https://bugzilla.redhat.com/show_bug.cgi?id=2365724 (secalert@redhat.com; Issue Tracking, Third Party Advisory)

- https://lists.libguestfs.org/archives/list/guestfs@lists.libguestfs.org/thread/67E7AASHHADIY7VAD3FFW2I67LTWVWYF/ (secalert@redhat.com; Third Party Advisory)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2025-47712; retrieved 2026-11-05; source updated 2026-11-05

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-47712; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-47712; retrieved 2026-11-05; source updated Not reported

Revision: efb3777eb02f3a9d48516c953c266f4ffaa67c84b9ac49bbca0d45735df89cef

Canonical: https://y2.dev/cve/CVE-2025-47712

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