smb: client: fix dir separator in SMB1 UNIX mounts (CVE-2026-31710) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-31710

smb: client: fix dir separator in SMB1 UNIX mounts

Answer in brief

CVE-2026-31710 records a Unknown severity vulnerability in smb: client: fix dir separator in SMB1 UNIX mounts. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), 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 May 1, 2026Updated Sep 21, 2026Source checked Sep 21, 2026First seen by HOL Sep 21, 2026Material review Sep 21, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
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), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=4fc3a433c13944ee5766ec5b9bf6f1eb4d29b880 <fbbfcf35e1ee3396631f3dc6214cb626aa9814c3 \|\| >=4fc3a433c13944ee5766ec5b9bf6f1eb4d29b880 <c4d3fc5844d685441befd0caaab648321013cdfd \|\| 9d9f6e06123001208cd8ae6332c7e814ab709169 \|\| >=6.18.53 <6.19	fbbfcf35e1ee3396631f3dc6214cb626aa9814c3, c4d3fc5844d685441befd0caaab648321013cdfd, 6.19
Linux/Linuxgeneric	7.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to fbbfcf35e1ee3396631f3dc6214cb626aa9814c3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
May 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 21, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix dir separator in SMB1 UNIX mounts When calling cifs_mount_get_tcon() with SMB1 UNIX mounts, @cifs_sb->mnt_cifs_flags needs to be read or updated only after calling reset_cifs_unix_caps(), otherwise it might end up with missing CIFS_MOUNT_POSIXACL and CIFS_MOUNT_POSIX_PATHS bits. This fixes the wrong dir separator used in paths caused by the missing CIFS_MOUNT_POSIX_PATHS bit in cifs_sb_info::mnt_cifs_flags.

Quoted source text, attributed separately from HOL analysis.