5.5

CVE-2026-31710: smb: client: fix dir separator in SMB1 UNIX mounts

Analyzed
AliasesUBUNTU-CVE-2026-31710
Published 01-05-2026Last modified 21-09-2026

Vulnerability summary

CVE-2026-31710 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.10% chance of exploitation in the next 30 days, higher than 0.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.10%
0%100%
Low · -0.04 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 6
OPENSUSE-SU-2026:10793-1USN-8488-1USN-8488-2USN-8507-1USN-8569-1USN-8603-1

Timeline

  1. 01-05-2026
    PublishedVulnerability first disclosed.
  2. 21-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.10%

Chance of exploitation in the next 30 days

Percentile

1%

Versus all other CVEs

30-day change

Decrease -0.04 pp

From 0.14% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu98 products
  • linux< 7.0.0-27.27
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 7.0.0-1008.8
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 4fc3a433c13944ee5766ec5b9bf6f1eb4d29b880, < fbbfcf35e1ee3396631f3dc6214cb626aa9814c3 | ≥ 4fc3a433c13944ee5766ec5b9bf6f1eb4d29b880, < c4d3fc5844d685441befd0caaab648321013cdfd | 9d9f6e06123001208cd8ae6332c7e814ab709169 | ≥ 6.18.53, < 6.19 | 7.0
  • linux_kernelEOL≥ 7.0.1, < 7.0.2 | 7.0 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6 | 7.0:rc7

2 vendors · 100 products

References

10 links