smb/client: flush dirty data before punching a hole (CVE-2026-93794) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-93794

smb/client: flush dirty data before punching a hole

Answer in brief

CVE-2026-93794 records a Unknown severity vulnerability in smb/client: flush dirty data before punching a hole. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6c265aca08155e519a8f6f6071c59dff4f535f70 \|\| >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <39562a56cdb515f6635c3e7bfe6629439b18a169 \|\| >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d7d2adcd022baade5cab65ca492ce63421ce3a6e \|\| >=0 <6.12.111 \|\| >=0 <6.18.53	6c265aca08155e519a8f6f6071c59dff4f535f70, 39562a56cdb515f6635c3e7bfe6629439b18a169, d7d2adcd022baade5cab65ca492ce63421ce3a6e, 6.12.111, 6.18.53

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux.
Review the reported fix. Update Linux/Linux to 6c265aca08155e519a8f6f6071c59dff4f535f70 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.