CVE-2026-31577

NameCVE-2026-31577
DescriptionIn the Linux kernel, the following vulnerability has been resolved: nilfs2: fix NULL i_assoc_inode dereference in nilfs_mdt_save_to_shadow_map The DAT inode's btree node cache (i_assoc_inode) is initialized lazily during btree operations. However, nilfs_mdt_save_to_shadow_map() assumes i_assoc_inode is already initialized when copying dirty pages to the shadow map during GC. If NILFS_IOCTL_CLEAN_SEGMENTS is called immediately after mount before any btree operation has occurred on the DAT inode, i_assoc_inode is NULL leading to a general protection fault. Fix this by calling nilfs_attach_btree_node_cache() on the DAT inode in nilfs_dat_read() at mount time, ensuring i_assoc_inode is always initialized before any GC operation can use it.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4664-1, DLA-4665-1, DLA-4671-1, DSA-6238-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.259-1fixed
bookworm, bookworm (security)6.1.176-1fixed
trixie6.12.94-1fixed
trixie (security)6.12.95-1fixed
forky, sid7.1.3-1fixed
linux-6.1 (PTS)bullseye (security)6.1.176-1~deb11u1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebullseye5.10.259-1DLA-4664-1
linuxsourcebookworm6.1.176-1DLA-4665-1
linuxsourcetrixie6.12.85-1DSA-6238-1
linuxsource(unstable)6.19.14-1
linux-6.1sourcebullseye6.1.176-1~deb11u1DLA-4671-1

Notes

https://git.kernel.org/linus/4a4e0328edd9e9755843787d28f16dd4165f8b48 (7.1-rc1)

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