CVE-2023-34256

NameCVE-2023-34256
DescriptionAn 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3508-1, DLA-3623-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.218-1fixed
bullseye (security)5.10.221-1fixed
bookworm6.1.94-1fixed
bookworm (security)6.1.99-1fixed
trixie6.9.9-1fixed
sid6.9.10-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebuster4.19.289-1DLA-3508-1
linuxsourcebullseye5.10.191-1
linuxsourcebookworm6.1.37-1
linuxsource(unstable)6.3.7-1unimportant
linux-5.10sourcebuster5.10.197-1~deb10u1DLA-3623-1

Notes

https://git.kernel.org/linus/4f04351888a83e595571de672e0a4a8b74f4fb31 (6.4-rc2)
Exploitable only when modifying block device while beeing mounted.

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