CVE-2025-47711 | 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.

Published: 2025-06-09 Last update: 2026-01-08 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-47711 is rated Moderate Risk (45.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.31%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-47711

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-05 0.05% 0.31% +0.26%
2 2025-07-11 0.04% 0.05% +0.01%
3 2025-06-09 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-47711

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]

Weakness enumeration for CVE-2025-47711

OS Trackers for CVE-2025-47711

vendor priority summary link
debian not yet assigned CVE-2025-47711 not yet assigned priority: Debian including 1 source packages (nbdkit), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2025-47711
redhat medium — https://access.redhat.com/security/cve/CVE-2025-47711
suse medium CVE-2025-47711 severity moderate: SUSE including 56 source package names (nbd, nbdkit-1.36.5-150400.3.9.1, …), 67 product×package rows across 7 product lines (SUSE Linux Enterprise Module for Package Hub 15 SP6, SUSE Linux Enterprise Module for Package Hub 15 SP7, … (7 product lines)): Fixed 64, Known Not Affected 3. https://www.suse.com/security/cve/CVE-2025-47711/
ubuntu medium CVE-2025-47711 medium priority: Ubuntu including 1 source packages (nbdkit), 8 status rows across 8 suites (focal, jammy, noble, oracular, plucky, questing, upstream, xenial): needs-triage 6, ignored 2. https://ubuntu.com/security/CVE-2025-47711

Affected software / configurations for CVE-2025-47711

Vendor Product Version Raw CPE
nbdkit_project nbdkit — cpe:2.3:a:nbdkit_project:nbdkit:-:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
redhat enterprise_linux 10.0 cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*
redhat enterprise_linux_advanced_virtualization 8.0 cpe:2.3:o:redhat:enterprise_linux_advanced_virtualization:8.0:*:*:*:*:*:*:*

References for CVE-2025-47711

cvelogic Threat Intelligence