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CVE-2021-3348

23
FAUCET Score

CVE-2021-3348 is a use-after-free vulnerability in the nbd_add_socket function within the Linux kernel's Network Block Device (NBD) driver, affecting versions up to 5.10.12, including Debian distributions. This flaw allows local attackers with NBD device access to trigger the vulnerability during device setup via a crafted I/O request. Rated with a CVSS score of 7.0 (High), successful exploitation could lead to high impact on confidentiality, integrity, and availability due to its low attack complexity and required low privileges. Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 5.10.12CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.0HIGH

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

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.0
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.25%
Probability of exploitation in next 30 days
EPSS Percentile
16.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0025 is in the 46th percentile among its peer group of 1,525 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.1 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (34)

microsoftpatch availablevia msrc
Product: 13851-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13852-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13853-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13854-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13855-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13856-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13857-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13858-12137Fixed in: -
microsoftpatch availablevia msrc
Product: 13859-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13860-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13861-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13862-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13863-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13864-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13865-12138Fixed in: -
microsoftpatch availablevia msrc
Product: 13866-12138Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-dtb-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-debuginfo-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-devel-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-drivers-accessibility-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-drivers-sound-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-docs-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-oprofile-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-tools-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-debuginfo-5.10.57.1-1.cm1.x86_64.rpm on CBL Mariner 1.0 x64Fixed in: -
microsoftpatch availablevia msrc
Product: kernel-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-devel-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-drivers-accessibility-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-drivers-sound-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-docs-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
microsoftpatch availablevia msrc
Product: kernel-tools-5.10.57.1-1.cm1.aarch64.rpm on CBL Mariner 1.0 ARMFixed in: -
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt-0:4.18.0-348.rt7.130.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-0:4.18.0-348.el8
View patch

Vendor Advisories (2)

microsoft2021-Feb/CVE-2021-3348

nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after-free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a certain point during device setup aka CID-b98e762e3d71.

Feb 9, 2021
redhatCVE-2021-3348Moderate

kernel: Use-after-free in ndb_queue_rq() in drivers/block/nbd.c

Jan 28, 2021

References

git.kernel.org / pub/scm/linux/kernel/git/torvalds/linux.git/commit
Mailing ListPatchVendor Advisory
lists.debian.org / debian-lts-announce/2021/03/msg00035.html
Third Party Advisory
openwall.com / lists/oss-security/2021/01/28/3
Mailing ListPatchThird Party Advisory
openwall.com / lists/oss-security/2021/02/01/1
Mailing ListPatchThird Party Advisory