← Vulnerability feed

Vulnerability record · CVE-2023-34256 · published 31 May 2023

CVE-2023-34256: Linux kernel out-of-bounds read vulnerability

Linux · Linux Kernel

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 an offset. NOTE: this is disputed by third parties because the kernel is not intended to defend against attackers with the stated "When modifying the block device while it is mounted by the filesystem" access.

5.5 CVSS 3.1 Medium EPSS 0.25% · top 83.9% CWE-125 · Out-of-bounds read
5.5CVSS 3.1 base score
0.25%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
12References
17 Jun 2026Last modified by NVD

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 an offset. NOTE: this is disputed by third parties because the kernel is not intended to defend against attackers with the stated "When modifying the block device while it is mounted by the filesystem" access.

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

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.suse.com/show_bug.cgi?id=1211895 Issue TrackingPatchThird Party Advisory
https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.3 Mailing ListPatch
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4f04351888a83e595571de672e0a4a8b74f4fb31 Mailing ListPatch
https://lists.debian.org/debian-lts-announce/2023/07/msg00030.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html Mailing ListThird Party Advisory
https://syzkaller.appspot.com/bug?extid=8785e41224a3afd04321 Mailing ListPatch
https://bugzilla.suse.com/show_bug.cgi?id=1211895 Issue TrackingPatchThird Party Advisory
https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.3.3 Mailing ListPatch
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4f04351888a83e595571de672e0a4a8b74f4fb31 Mailing ListPatch
https://lists.debian.org/debian-lts-announce/2023/07/msg00030.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html Mailing ListThird Party Advisory
https://syzkaller.appspot.com/bug?extid=8785e41224a3afd04321 Mailing ListPatch

Track CVE-2023-34256 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2025-32433Erlang/OTP SSH server missing authentication allows remote code executionErlang/OTP SSH servers before OTP-27.3.3, OTP-26.2.5.11 and OTP-25.3.2.20 mishandle SSH protocol messages, letting an unauthenticated attacker execut…KEVEPSS 99%analysed10.0CVE-2025-24201Apple WebKit out-of-bounds write allows sandbox escapeCVE-2025-24201 is an out-of-bounds write in Apple's WebKit that was addressed with improved checks. Maliciously crafted web content may break out of …KEVEPSS 3.8%analysed10.0CVE-2021-44228Apache Log4j2 JNDI lookup remote code executionApache Log4j2 versions 2.0-beta9 through 2.15.0 (excluding 2.12.2, 2.12.3, and 2.3.1) do not protect against attacker-controlled LDAP and other JNDI …KEVEPSS 100%analysed10.0CVE-2015-3306ProFTPD mod_copy arbitrary file read and writeThe mod_copy module in ProFTPD 1.3.5 fails to restrict the SITE CPFR and SITE CPTO commands, letting remote attackers copy arbitrary files on the ser…KEVEPSS 99%analysed9.8CVE-2026-24061GNU Inetutils telnetd argument injection allows remote auth bypasstelnetd in GNU Inetutils through 2.7 fails to sanitize the USER environment variable, so a value such as "-f root" is passed as an argument to login …KEVEPSS 99%analysed9.8CVE-2025-39682Linux kernel TLS zero-length record handling flaw on rx_listThe Linux kernel TLS receive path mishandles zero-length records that arrive from the rx_list, breaking the assumption that a record type change cann…KEVEPSS 3.3%analysed9.8CVE-2025-24813Apache Tomcat Default Servlet path equivalence enables RCE and file disclosureApache Tomcat mishandles path equivalence for names containing an internal dot, letting a remote unauthenticated attacker write files through the Def…KEVEPSS 100%analysed9.8CVE-2024-9680Mozilla Firefox and Thunderbird use-after-free in Animation timelinesA use-after-free flaw in Animation timelines allows an attacker to execute code in the content process of Firefox and Thunderbird. Mozilla reports ex…KEVEPSS 23%analysed

Source: NIST National Vulnerability Database (record CVE-2023-34256), CISA KEV, FIRST EPSS (scores of 2026-11-14). This page is refreshed as NVD updates the record.