CVE-2025-47711Network attack vector

Authenticated server crash via oversized block-status extent

Published Jun 9, 2025 · Updated Jun 30, 2026

Off-by-one error in nbdkit allows remote authenticated users to crash the server via a maximum-length block-status request. The extents_to_block_descriptors loop fails to stop when a plugin extent fills or exceeds the 32-bit request length, then reaches an assertion while processing the remainder. Exploitation requires valid access to an NBD export and interrupts the server for other clients without reported data disclosure or modification.

CVSS severity6.5
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Off-by-one error in nbdkit allows remote authenticated users to crash the server via a maximum-length block-status request. The extents_to_block_descriptors loop fails to stop when a plugin extent fills or exceeds the 32-bit request length, then reaches an assertion while processing the remainder. Exploitation requires valid access to an NBD export and interrupts the server for other clients without reported data disclosure or modification.

The record

CVE
CVE-2025-47711
Published
Jun 9, 2025
Updated
Jun 30, 2026
Vendor
389 Directory Server
Product
nbdkit
Classifications
CWE-193, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.11.10 <1.38.6
  2. Affected versionversion=1.40.0 <1.40.6
  3. Affected versionversion=1.42.0 <1.42.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

389 Directory Server · nbdkitversion=1.11.10 <1.38.6; version=1.40.0 <1.40.6; version=1.42.0 <1.42.3
389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

Published CVSS scores

6.5Red HatCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.5CVE ProgramCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-193Off-by-one Error
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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