// For flags

CVE-2023-5215

Libnbd: crash or misbehaviour when nbd server returns an unexpected block size

Severity Score

6.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A flaw was found in libnbd. A server can reply with a block size larger than 2^63 (the NBD spec states the size is a 64-bit unsigned value). This issue could lead to an application crash or other unintended behavior for NBD clients that doesn't treat the return value of the nbd_get_size() function correctly.

Se encontró una falla en libnbd. Un servidor puede responder con un tamaño de bloque mayor que 2^63 (la especificación NBD establece que el tamaño es un valor sin signo de 64 bits). Este problema podría provocar un bloqueo de la aplicación u otro comportamiento no deseado para los clientes NBD que no traten correctamente el valor de retorno de la función nbd_get_size().

This update for libnbd fixes the following issues. Updated to version 1.18.1 Updated to version 1.18.0. Fixed an issue where an NBD server returning an unexpected block size might crash an application.

*Credits: N/A
CVSS Scores
Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Adjacent
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Adjacent
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2023-09-26 CVE Reserved
  • 2023-09-28 CVE Published
  • 2025-08-06 CVE Updated
  • 2025-08-06 First Exploit
  • 2025-08-11 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-241: Improper Handling of Unexpected Data Type
  • CWE-252: Unchecked Return Value
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Redhat
Search vendor "Redhat"
 Libnbd
Search vendor "Redhat" for product "Libnbd"
 < 1.18.0
Search vendor "Redhat" for product "Libnbd" and version " < 1.18.0"
-
Affected
Redhat
Search vendor "Redhat"
 Enterprise Linux
Search vendor "Redhat" for product "Enterprise Linux"
 8.0
Search vendor "Redhat" for product "Enterprise Linux" and version "8.0"
-
Affected
Redhat
Search vendor "Redhat"
 Enterprise Linux
Search vendor "Redhat" for product "Enterprise Linux"
 9.0
Search vendor "Redhat" for product "Enterprise Linux" and version "9.0"
-
Affected