CVE-2023-34256 Information disclosure in n/a

What is CVE-2023-34256?

CVE-2023-34256 is a medium-severity vulnerability in Debian Debian Linux, published on 31 May 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-125

Which versions are affected by CVE-2023-34256?

It affects 3 products.

Products include Debian Debian Linux, Linux kernel, Suse Linux Enterprise.

How do I fix CVE-2023-34256?

Apply the vendor's patch.

Is CVE-2023-34256 being exploited?

There is no known exploitation of CVE-2023-34256 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-27063, DEBIAN-CVE-2023-34256, GHSA-rj85-7vr5-qv74, UBUNTU-CVE-2023-34256.