Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2023-5215

19
FAUCET Score

CVE-2023-5215 is a medium-severity flaw in libnbd, affecting Red Hat Enterprise Linux and libnbd, where a malicious NBD server can send a block size exceeding 2^63. This can cause NBD clients that mishandle the nbd_get_size() return value to crash or exhibit other unintended behavior. The vulnerability has a CVSS score of 6.5 (Medium), indicating an adjacent network attack vector with low complexity and high availability impact, but no confidentiality or integrity impact. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.18.0CPE matchmatch criteria
cpe:2.3:a:redhat:libnbd:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
ADJACENT_NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.6
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.75%
Probability of exploitation in next 30 days
EPSS Percentile
51.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0075 is in the 80th percentile among its peer group of 1,802 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (13)

microsoftpatch availablevia msrc
Product: azl3 libnbd 1.12.1-3 on Azure Linux 3.0Fixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: 18301-16823Fixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: 18302-17084Fixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.12.1-3
microsoftpatch availablevia msrc
Product: cbl2 libnbd 1.12.1-3 on CBL Mariner 2.0Fixed in: 1.12.1-3
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: libnbd-0:1.18.1-3.el9
View patch
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8 Advanced VirtualizationFixed in: virt-devel:av/libnbd
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: virt:rhel/libnbd
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8 Advanced VirtualizationFixed in: virt:av/libnbd
redhatvendor investigatingvia nvd_reference
View patch

Vendor Advisories (3)

microsoft2024-Jun/CVE-2023-5215

CVE-2023-5215

Jun 11, 2024
redhatCVE-2023-5215Low

libnbd: Crash or misbehaviour when NBD server returns an unexpected block size

Sep 21, 2023
microsoft2023-Sep/CVE-2023-5215Moderate

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

Sep 12, 2023

References

access.redhat.com / errata/RHSA-2024:2204
access.redhat.com / security/cve/CVE-2023-5215
Vendor Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingVendor Advisory
listman.redhat.com / archives/libguestfs/2023-September/032635.html
ExploitPatch