CVE-2026-93794 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-DEBIAN12-LINUX612-20507434
  • published5 Oct 2026
  • disclosed24 Sept 2026

Introduced: 24 Sep 2026

NewCVE-2026-93794  (opens in a new tab)

How to fix?

Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

In 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.

CVSS Base Scores

version 3.1