CVE-2026-93794

NameCVE-2026-93794
DescriptionIn the Linux kernel, the following vulnerability has been resolved: smb/client: flush dirty data before punching a hole Punching a hole after a large buffered write may leave the range reported as data. Reproduce it with: xfs_io -f \ -c "pwrite -b 3m -S 0x61 0 3m" \ -c "fpunch 1m 1m" \ -c "seek -h 0" \ -c "seek -d 1m" \ /mnt/test/repro Punching 1 MiB at offset 1 MiB should produce: 0 1 MiB 2 MiB 3 MiB | DATA | HOLE | DATA | EOF Instead, the entire file is reported as data. SEEK_HOLE(0) returns EOF, and SEEK_DATA(1M) returns 1M. This happens because a dirty folio spanning the punched range can be written back after the punch and refill the hole. Fix this by flushing and waiting for dirty data in the punched range before invalidating the page cache and issuing FSCTL_SET_ZERO_DATA. The xfstests generic/539 pass against Samba/ksmbd with this change.
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-4817-1, DSA-6528-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bookworm6.1.176-1vulnerable
bookworm (security)6.1.187-1vulnerable
trixie6.12.107-1vulnerable
trixie (security)6.12.111-1fixed
forky7.2.9-1fixed
sid7.2.10-1fixed
linux-6.12 (PTS)bookworm (security)6.12.111-1~deb12u1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcetrixie6.12.111-1DSA-6528-1
linuxsource(unstable)7.2.6-1
linux-6.12sourcebookworm6.12.111-1~deb12u1DLA-4817-1

Notes

https://git.kernel.org/linus/d7d2adcd022baade5cab65ca492ce63421ce3a6e (7.2-rc4)

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