01 Record

CVE-2023-34256

An issue was discovered in the Linux kernel before 6.3.3. There is an out-of-bounds read in crc16 in lib/crc16.c when called from fs/ext4/super.c because ext4_group_desc_csum does not properly check

MediumPUBLISHEDCNA: mitre

CNA base score5.5 CVSS v3.xCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

View raw JSON

02 Description

An issue was discovered in the Linux kernel before 6.3.3. There is an out-of-bounds read in crc16 in lib/crc16.c when called from fs/ext4/super.c because ext4_group_desc_csum does not properly check

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.24% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 15.7% of scored records. A rank, not a probability.

NVD base score

5.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2023-05-31 00:00Z3 YR AGO

Last updated

2025-03-11 15:34Z1 YR AGO

Reserved

2023-05-31

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Medium (CVSS 5.5)

CNA CVSS vector

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

Weaknesses

CWE-125Out-of-bounds ReadBase

Data version

5.1

Document digest

6f44943ea4fbb262bea5f4a9860045fdbf05f69ffcea7286b39a2f7f17993659

05 Affected products

VendorProductVersionsPlatforms

debiandebian_linuxNot specified—

linuxlinux_kernelNot specified—

suselinux_enterpriseNot specified—

06 References

syzkaller.appspot.comhttps://syzkaller.appspot.com/bug?extid=8785e41224a3afd04321
git.kernel.orghttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4f04351888a83e595571de672e0a4a8b74f4fb31
cdn.kernel.orghttps://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.3
bugzilla.suse.comhttps://bugzilla.suse.com/show_bug.cgi?id=1211895
lists.debian.org[debian-lts-announce] 20230727 [SECURITY] [DLA 3508-1] linux security updatehttps://lists.debian.org/debian-lts-announce/2023/07/msg00030.htmlmailing-list
lists.debian.org[debian-lts-announce] 20231019 [SECURITY] [DLA 3623-1] linux-5.10 security updatehttps://lists.debian.org/debian-lts-announce/2023/10/msg00027.htmlmailing-list

07 Fixed in

Debian 12

linux
Fixed in 6.1.37-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

linux
Fixed in 6.3.7-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

linux
Fixed in 6.3.7-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.