Missing Synchronization Affecting kernel6.12-debuginfo package, versions <1:6.12.111-136.204.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL612DEBUGINFO-20860434
  • published13 Oct 2026
  • disclosed24 Sept 2026

Introduced: 24 Sep 2026

NewCVE-2026-93794  (opens in a new tab)
CWE-820  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.12-debuginfo to version 1:6.12.111-136.204.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3193.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.12-debuginfo package and not the kernel6.12-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 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