CVE-2026-74608: smb: client: Fix use-after-free in cifs_try_adding_channels()

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.5%

EPSS score, percentile 41.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• from 6.1.78 to before 6.1.183
• from 6.6.17 to before 6.6.152
• from 6.7.5 to before 6.8
• 6.8

Unaffected before 6.8; 6.1.183; 6.6.152; 6.12.104; 6.18.45; 7.1.9; and 1 more

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unaffected.

Versions not listed are: affected.

Versions the record lists as unaffected: 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after-free in cifs_try_adding_channels() cifs_try_adding_channels() takes a temporary reference to an interface before dropping iface_lock. If cifs_ses_add_channel() fails, it drops that reference and then increments iface->weight_fulfilled. A concurrent interface list refresh can remove the list reference…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-74608 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 22 Aug 2026.
• The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.5% (percentile 41.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

smb: client: Fix use-after-free in cifs_try_adding_channels()

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after-free in cifs_try_adding_channels() cifs_try_adding_channels() takes a temporary reference to an interface before dropping iface_lock. If cifs_ses_add_channel() fails, it drops that reference and then increments iface->weight_fulfilled. A concurrent interface list refresh can remove the list reference while channel creation is in progress. In that case, the failure-path kref_put() releases the last reference and frees iface. Updating weight_fulfilled afterward then accesses freed memory. Increment weight_fulfilled before dropping the temporary reference, keeping iface alive for the final access.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline

Known exploited Linux vulnerabilities

• CVE-2026-46300: Linux Kernel Missing Initialization of a Variable Vulnerability (added 28 Oct 2026)
• CVE-2025-39682: Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability (added 18 Sep 2026)
• CVE-2025-39964: Linux Kernel Race Condition Vulnerability (added 18 Sep 2026)
• CVE-2026-53266: Linux Kernel Out-of-Bounds Write Vulnerability (added 18 Sep 2026)
• CVE-2026-53362: Linux Kernel Unspecified Vulnerability (added 27 Aug 2026)